fergal@chromium.org bfcache-dev@chromium.org Records the reason why the page is evicted from the back-forward cache but after the document is restored. This happens when there is a race between eviction and restoring. This also records when the page is restored to calculate how often this eviction happens. This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history, this records whether the page was restored from the BackForwardCache or not. This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history, this records what blocklisted features were used when the page was loaded and prevented this page from being stored in the back-forward cache. Multiple blocklisted features can be recorded for the same page. This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history and the BackForwardCache wasn't used because of the other active WebContents objects in the BrowsingInstance, this records the reason why the browsing instance wasn't swapped. This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org rakina@chromium.org bfcache-dev@chromium.org For history navigations, records the reason passed to BackForwardCache::DisableForRenderFrameHost calls. The metric is recorded when a history navigation commits and emits a sample for each reason. Compare this with BackForwardCache.HistoryNavigationOutcome, which contains the total number of navigations which where not cached This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history, record why it wasn't restored from the cache. The page might not have entered the back-forward in the first place based on the features used, or it might have been evicted while being in the cache. This is recorded for all websites regardless of whether back-forward cache is enabled or not. yuzus@chromium.org bfcache-dev@chromium.org This metric is emitted when we try to enforce the cache size limit, which is 1) when a page enters BackForwardCache and 2) when a page entering BackForwardCache receives an acknowledgement from the renderer. This reports the number of the entries that have not received an acknowledgement from the renderer. fergal@chromium.org bfcache-dev@chromium.org Records the reason why the page is evicted from the back-forward cache but after the document is restored. This happens when there is a race between eviction and restoring. This also records when the page is restored to calculate how often this eviction happens. This is recorded when back-forward cache is enabled for this navigation (back-forward cache feature is enabled and the domain is in the scope of the experiment). rakina@chromium.org bfcache-dev@chromium.org Records the reason of renderer-initiated back-forward cache eviction. Emitted when renderer evicts the page from back-forward cache. fergal@chromium.org bfcache-dev@chromium.org Records the time duration between the last time when the entry goes to the back-forward cache and the time when the process is killed. fergal@chromium.org bfcache-dev@chromium.org Track number of times an unexpected IPC message is posted to frames in the renderer process while they are frozen in the back-forward cache. IPC tasks are denoted by md5 hash of the mojo bindings method name or message hash for legacy IPCs. Recorded when an IPC task is posted to frames that have already been stored in the back-forward cache, after a 15 second delay to account for completion of all freezing-related operations. fergal@chromium.org bfcache-dev@chromium.org Duration between start of page being stored in the back-forward cache and when the unexpected IPC call is received by a frame while in the cache. Recorded when an IPC task is posted to frames that have already been stored in the back-forward cache, after a 15 second delay to account for completion of all freezing-related operations. fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history, this records whether the page was restored from the BackForwardCache or not. This is recorded when back-forward cache is enabled for this navigation (back-forward cache feature is enabled and the domain is in the scope of the experiment). fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history, this records what blocklisted features were used when the page was loaded and prevented this page from being stored in the back-forward cache. Multiple blocklisted features can be recorded for the same page. This is recorded when back-forward cache is enabled for this navigation (back-forward cache feature is enabled and the domain is in the scope of the experiment). fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history and the BackForwardCache wasn't used because of the other active WebContents objects in the BrowsingInstance, this records the reason why the browsing instance wasn't swapped. This is recorded when back-forward cache is enabled for this navigation (back-forward cache feature is enabled and the domain is in the scope of the experiment). fergal@chromium.org bfcache-dev@chromium.org For history navigations, records the reason passed to BackForwardCache::DisableForRenderFrameHost calls. The metric is recorded when a history navigation commits and emits a sample for each reason. Compare this with BackForwardCache.HistoryNavigationOutcome, which contains the total number of navigations which where not cached This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org bfcache-dev@chromium.org For history navigations, records the reason passed to RenderFrameHost::IsInactiveAndDisallowActivation calls. The metric is recorded when a history navigation commits and emits a sample for each reason. Compare this with BackForwardCache.HistoryNavigationOutcome, which contains the total number of navigations which where not cached This is recorded for all websites regardless whether back-forward cache is enabled or not. yuzus@chromium.org bfcache-dev@chromium.org For history navigations, records the AX event type that caused RenderFrameHost::IsInactiveAndDisallowActivation calls. The value refers to AX enum in ui/accessibility/ax_enums.mojom. The metric is recorded when a history navigation commits and emits the breakdown of a specific bucket in HistoryNavigationOutcome.NotRestoredReason (AXEvent). Compare this with BackForwardCache.HistoryNavigationOutcome, which contains the total number of navigations which were not cached. This is recorded for all websites regardless whether back-forward cache is enabled or not. fergal@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history, record why it wasn't restored from the cache. The page might not have entered the back-forward in the first place based on the features used, or it might have been evicted while being in the cache. This is recorded when back-forward cache is enabled for this navigation (back-forward cache feature is enabled and the domain is in the scope of the experiment). rakina@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history and the BackForwardCache wasn't used because of other active WebContents objects in the BrowsingInstance, this records the number of other active pages/related active contents using the same BrowsingInstance. rakina@chromium.org bfcache-dev@chromium.org When navigating back to a page in the session history and the BackForwardCache wasn't used because of other active WebContents objects in the BrowsingInstance, this Records whether the page was potentially synchronously accessible by other pages/related active contents using the same BrowsingInstance, at the time the page was navigated away from. altimin@chromium.org hajimehoshi@chromium.org bfcache-dev@chromium.org Records whether a page restored from the back-forward cache has pageshow handlers installed in its main frame. Recorded when the renderer resumes page when restoring it from the back-forward cache. wenyufu@chromium.org bfcache-dev@chromium.org Record for a page that has form attached is about to restored from the back forward cache, to understand the success rate for bfcaching a page that has form / input entry attached. This is recorded for page with form attached only. Recorded during a cross-page history navigation. If a page with form is restored from the cache, "PageRestored" will be recorded; if the page is not egligible to be restored due to any reason, "PageNotRestored" will be recorded. wenyufu@chromium.org bfcache-dev@chromium.org Record for a page that has form attached is egligible to be stored in back forwad cache, to understand the success rate for bfcaching a page that has form / input entry attached. This is recorded for page with form attached only. Recorded when a navigation is committed. If a page has form attached "PageSeen" will be recorded; if the page is egligible to be stored in the back forward cache, "PageStored" will be recorded. rakina@chromium.org bfcache-dev@chromium.org Whether a back/forward cached page shares the same process as the page that we're navigating to (i.e. whether the new active page reuses the process of the back/forward cached page). Recorded when navigating away from a page, after the navigation commits and we're about to put the previous page into the back/forward cache. sreejakshetty@chromium.org altimin@chromium.org bfcache-dev@chromium.org Duration between start of navigation restoring a document from back-forward cache and the first paint. This is recorded when a history navigation is served from back-forward cache but in a foreground tab. fergal@google.com bfcache-dev@chromium.org Hash (base::HashMetricName) of a mojo interface name. A sample is recorded for every message the browser receives from a renderer for a page that is in the back-forward cache. Logging can be disabled via the back-forward cache feature parameter "message_handling_when_cached". Renderers should not be sending messages back to the browser for pages that are in the back-forward cache. Eventually we will be killing such renderers (as we could assume that it is misbehaving because it got compromised). But first we must make sure that we are not sending messages by mistake (i.e. bugs in the renderer). arthursonzogni@chromium.org chrome-security-owp-team@google.com Record whether iframe with the anonymous attribute contains sandboxed document or not. lbrady@google.com shivanisha@chromium.org Record if a 'reserved.top_navigation' automatic beacon was sent out, or the reason for not sending the beacon if it was not sent out. clamy@chromium.org The cache flags set on back-forward navigations. shivanisha@chromium.org csharrison@chromium.org This metric logs true if the existing entry being navigated to is marked to be skipped on back/forward UI. This is logged at the start of navigation initiated using long-press back/forward button. leimy@chromium.org bfcache-dev@chromium.org The time spent between the back navigation menu model's opening and the activation of a menu item. This is recorded when the back navigation menu model receives signal that indicates the item from the menu is activated. See `BackForwardMenuModel::MenuWillShow()` and `BackForwardMenuModel::ActivatedAt()` for more details. leimy@chromium.org bfcache-dev@chromium.org The time spent between the back navigation menu model's opening and the closing. There might or might not be a menu item activation in between. This is recorded when the back navigation menu model receives signal that indicates it will be closed. See `BackForwardMenuModel::MenuWillShow()` and `BackForwardMenuModel::MenuWillClose()` for details. clamy@chromium.org Whether the back-forward navigation was served from cache. xiaochenzh@chromium.org shivanisha@chromium.org For navigation requests with FLEDGE or SharedStorage generated urn:uuid, record whether it is rendered in a fenced frame or iframe. Recorded when navigation requests begin (i.e. during NavigationRequest::BeginNavigation()). cduvall@chromium.org jam@chromium.org Measures how long it takes to fetch from the code cache. Logged every time the code cache is fetched for the navigation body or a resource. peilinwang@google.com woa-performance-bugs+jank@google.com Measures the amount of time it takes to call RenderFrameHostImpl::DidCommitSameDocumentNavigation(). Logged once per call to RenderFrameHostImpl::DidCommitSameDocumentNavigation(). csharrison@chromium.org yaoxia@chromium.org When a navigation results in a download, logs the download policy applied to that navigation. This is logged once per download and when multiple policies exist, an arbitrary one will be chosen. csharrison@chromium.org yaoxia@chromium.org When a navigation results in a download, for each download policy applied to that navigation, logs the policy. bashi@chromium.org chrome-loading@google.com Time from a navigation request received the first early hints to the response started. Recorded per navigation when both early hints and the final response are received. bashi@chromium.org chrome-loading@google.com Time from a navigation request will start to the first early hints is received. Recorded per navigation when both early hints and the final response are received. alexmos@chromium.org creis@chromium.org If a navigation swaps to the destination RenderFrameHost early, this records whether or not the navigation actually ended up committing a document. This will be true for most navigations, but false for downloads and 204 responses. Recorded once for every navigation that performs an early RenderFrameHost swap. alexmos@chromium.org creis@chromium.org If a navigation swaps to the destination RenderFrameHost early, this records whether the navigation was in an outermost main frame. Recorded once per early RenderFrameHost swap. alexmos@chromium.org creis@chromium.org This records whether a navigation swapped to the destination RenderFrameHost early (prior to commit), as well as the reason for this swap. Recorded once at the end of every navigation, when NavigationRequest is destroyed. estark@chromium.org security-enamel@chromium.org The amount of time that an HTTP page was in the foreground. Recorded on every page close/transition. This metric is exposed publicly on the HTTPS Transparency Report at https://transparencyreport.google.com/https/overview?hl=en. estark@chromium.org security-enamel@chromium.org The amount of time that an HTTPS page was in the foreground. Recorded on every page close/transition. This metric is exposed publicly on the HTTPS Transparency Report at https://transparencyreport.google.com/https/overview?hl=en. estark@chromium.org security-enamel@chromium.org The percentage of time that HTTPS pages were in the foreground, as compared to total foreground time. Recorded whenever user metrics are uploaded. lbrady@google.com shivanisha@chromium.org This records top-level navigations that originated from a fenced frame or URN iframe. At navigation start, a 'Begin' is logged. If the navigation commits (i.e. doesn't fail at some point in the navigation process), a 'Commit' is logged. To get the percentage of top-level navigations originating from a fenced frame or URN iframe that successfully commit, divide the number of 'Commit' logs by the number of 'Begin' logs. peilinwang@google.com woa-performance-bugs+jank@google.com Measures the amount of time it takes to call RenderFrameHostManager::GetFrameHostForNavigation(). Logged once per call to RenderFrameHostManager::GetFrameHostForNavigation(), most often two times per navigation. alexmos@chromium.org creis@chromium.org wjmaclean@chromium.org Whether the committing guest navigation targets an HTTP(S) URL. Logged at ready-to-commit time for navigations in a webview tag (also known as "guest" in process model terminology), excluding same-document navigations and errors. alexmos@chromium.org creis@chromium.org wjmaclean@chromium.org Whether the committing guest navigation is in a main frame. Logged at ready-to-commit time for navigations in a webview tag (also known as "guest" in process model terminology), excluding same-document navigations and errors. mpearson@chromium.org amaralp@chromium.org chrome-analysis-team@google.com Emitted every time a user uses a Home button to go to their home page. Records whether the page is chrome-internal (most likely the New Tab Page or about:blank) or not (most likely an actual web site). For the purpose of this histogram, about:, chrome: and chrome-native: are considered chrome-internal; everything else is not. The user action Navigation.Home.NotChromeInternal is also logged in the case that false is logged to this histogram. This histogram is of special interest to the chrome-analysis-team@. Do not change its semantics or retire it without talking to them first. meacer@chromium.org chrome-trusty-transport@google.com Counts the number of typed and pasted main frame navigations to hostnames that contain characters that are treated differently between IDNA 2003 and IDNA 2008, aka deviation characters. Ignores reload navigations. alexmos@chromium.org creis@chromium.org wjmaclean@chromium.org Whether the committing navigation is for a webview tag (also known as "guest" in process model terminology). Logged at ready-to-commit time for every navigation, excluding same-document navigations and errors. alexmos@chromium.org lukasza@chromium.org Whether the navigation commits in a process that is locked to an origin. Logged at ready-to-commit time for every navigation excluding same-document navigations and errors. alexmos@chromium.org lukasza@chromium.org Whether the navigation commits in a process that is locked to an origin. Logged at ready-to-commit time for every navigation that commits with a HTTP or HTTPS URL scheme, excluding same-document navigations and errors. arthursonzogni@chromium.org clamy@chromium.org nasko@chromium.org Whether a main frame navigation led to a change of BrowsingInstance or not. arthursonzogni@chromium.org clamy@chromium.org nasko@chromium.org Whether the navigation led to a change of SiteInstance or not. ryansturm@chromium.org spelchat@chromium.org The time the user waits beyond what is configured for the latency ablation study. The enabled arms of the latency ablation study prescribe an amount of time to delay the navigation, and this histogram records the amount of time that was waited beyond that prescription. Recorded upon resuming the navigation after the ablation occurs. This ablation occurs for most navigations, but does not occur for subframes, prerenders, fenced frames, bf/restore style navigations, and client redirects. The experiment can be configured to only affect default search (or only affect non default search). boliu@chromium.org alexmos@chromium.org src/base/android/OWNERS The type of the source of a load from LoadIfNecessary. Recorded when LoadIfNecessary starts a page load. For example, on Android, kRequestedByClient is recorded when user switch back to a tab with a dead renderer, which causes the tab to reload. michaelpg@chromium.org yilkal@chromium.org cros-families-eng@google.com The number of frames that are present in a WebContents. Recorded once when the main frame finishes loading. michaelpg@chromium.org yilkal@chromium.org cros-families-eng@google.com The maximum number of loaded frames that are present in a WebContents. Recorded once when the main frame is moving away from current page. This can be when the WebContents is being destroyed or when it starts loading new content. yaoxia@chromium.org cammie@chromium.org Whether the initiator frame is present when a renderer-initiated primary main frame navigation has started. Recorded for each renderer-initiated primary main frame navigation when the navigation has started (i.e. during WebContentsObserver::DidStartNavigation()). meacer@chromium.org security-enamel@chromium.org Site engagement level of the URL of the top frame of a navigation. Only counts HTTP or HTTPS URLs and ignores downloads. dullweber@chromium.org feuunk@chromium.org Records whether third party cookie blocking was enabled for a site. Recorded for each main-frame navigation when that navigation commits. Only counts HTTP or HTTPS URLs and ignores downloads. meacer@chromium.org security-enamel@chromium.org Site engagement level of the URL of the top frame of a form submission. This is a subset of Navigation.MainFrame.SiteEngagementLevel. cthomp@chromium.org trusty-transport@chromium.org Whether the main-frame navigation was to a URL with an RTL domain name. This is only recorded for finished navigations and not attempts. Warning: this histogram was expired from M92 through M95; data may be missing. cthomp@chromium.org trusty-transport@chromium.org Whether the main-frame navigation was to a URL with an RTL domain name, recorded for each main-frame avigation that replaces a document object. This is not reported for reference fragment navigations, pushState/replaceState or same page history navigation. This is only recorded for finished navigations and not attempts. rhalavati@chromium.org chrome-privacy-core@google.com The browser profile type for each main-frame navigation, recorded after navigation completion, including NTP. estark@chromium.org elawrence@chromium.org trusty-transport@chromium.org The scheme of the URL for each main-frame navigation. This is only recorded for finished navigations and not attempts. Warning: this histogram was expired from 2021-06-01 through M95; data may be missing. estark@chromium.org elawrence@chromium.org trusty-transport@chromium.org The scheme of the URL for each main-frame navigation that replaces a document object. This is not reported for reference fragment navigations, pushState/replaceState or same page history navigation. This is only recorded for finished navigations and not attempts. estark@chromium.org elawrence@chromium.org trusty-transport@chromium.org The scheme of the URL for each main-frame navigation that replaces a document object while in incognito. This is not reported for reference fragment navigations, pushState/replaceState or same page history navigation. This is only recorded for finished navigations and not attempts. elawrence@chromium.org estark@chromium.org The scheme of the URL for each main-frame navigation while in incognito. This is only recorded for finished navigations and not attempts. Warning: this histogram was expired from 2021-06-01 through M97; data may be missing. Obsolete after 2022-06-30. rakina@chromium.org dcheng@chromium.org Records whether a speculative RenderFrameHost for an older navigation existed when a new NavigationRequest is created, causing the speculative RenderFrameHost to be deleted. sky@chromium.org swarm-team@chromium.org Time from navigation start to before task is posted to continue with navigation. This is only logged if there are no before-unload handlers and a post task is used rather than synchronously continuing (referred to as for_legacy in code). sky@chromium.org swarm-team@chromium.org Time from navigation start to calling NavigationRequest::BeginNavigation(). This is only logged if before-unload handlers are skipped because the feature AvoidUnnecessaryBeforeUnloadCheckSync is enabled. sky@chromium.org jam@chromium.org Time it takes for the renderer to receive the request to process before-unload handlers. sky@chromium.org jam@chromium.org Time it takes for navigation to start when a PostTask() is used for legacy before-unload handlers. Only logged if the feature AvoidUnnecessaryBeforeUnloadCheck is enabled. clamy@chromium.org nasko@chromium.org Overhead time spent handling the OnBeforeUnload event from the browser standpoint. More precisely, it is the total time between dispatch and acknowledgment of the BeforeUnload event on the browser side, minus the actual time spent executing the BeforeUnload handlers on the renderer side. chikamune@chromium.org chrome-loading@google.com Milliseconds spent to process all the beforeunload events in JavaScript and waiting time for beforeunload dialog is closed if necessary. Recorded only when a non-reload navigation occurs. alexmos@chromium.org creis@chromium.org wjmaclean@chromium.org For every successful cross-document commit, this logs whether or how OriginAgentCluster was involved. It tracks whether it was requested, as well as whether the isolation was granted, which can be affected by other documents in the same browsing context group. If OriginAgentCluster-by- default is not enabled, the first four enum values track this state. If OriginAgentCluster-by-default is enabled, then the second (disjoint) set of six enum values tracks this state, plus the two additional cases where OriginAgentCluster was explicitly not requested, and was or wasn't granted. dcheng@chromium.org rakina@chromium.org Records how many attempts to assign a final RenderFrameHost for a navigation were blocked due to a pre-existing speculative RenderFrameHost being in the kPendingCommit state. Collected when the navigation commits in DidCommitNavigation(). dcheng@chromium.org rakina@chromium.org Records how many attempts to assign RenderFrameHost (initial or final) for a navigation were blocked due to a pre-existing speculative RenderFrameHost being in the kPendingCommit state. Collected when the navigation commits in DidCommitNavigation(). dcheng@chromium.org rakina@chromium.org Records whether any calls to `GetFrameHostForNavigation()` that failed due to a pre-existing speculative RenderFrameHost being in the kPendingCommit state. Collected when the navigation commits in DidCommitNavigation(). dcheng@chromium.org rakina@chromium.org Measures the amount of time between the browser asking a speculative RenderFrameHost to commit a navigation in the renderer and the commit actually being recorded in the browser process. Collected when the navigation commits in DidCommitNavigation(). alexilin@chromium.org blundell@chromium.org lizeb@chromium.org pasko@chromium.org Measures the amount of time that a requested preresolve job spends queueing before being executed (e.g., due to a max # of preconnects being in flight). Recorded for each presolve job. alexilin@chromium.org blundell@chromium.org lizeb@chromium.org pasko@chromium.org Measures the length of the queue of preresolve jobs at the beginning of PreconnectManager processing this queue to execute jobs. Recorded each time that PreconnectManager processes the queue of pending jobs. alexilin@chromium.org blundell@chromium.org lizeb@chromium.org pasko@chromium.org Measures the amount of time that the task corresponding to the completion callback for a proxy lookup performed as part of navigation preconnect spent being queued before executing. Recorded for each proxy lookup. alexilin@chromium.org lizeb@chromium.org pasko@chromium.org Measures the duration from initiation to completion for a proxy lookup performed as part of navigation preconnect. Recorded for each proxy lookup. Note: Does not capture any delay spent queuing *before* initiating the proxy lookup (e.g., due to a max # of preconnects being in flight). alexilin@chromium.org blundell@chromium.org lizeb@chromium.org pasko@chromium.org Measures the amount of time that the task corresponding to the completion callback for a host resolution performed as part of navigation preconnect spent being queued before executing. Recorded for each host resolution. alexilin@chromium.org lizeb@chromium.org pasko@chromium.org Measures the duration from initiation to completion for a host resolution performed as part of navigation preconnect. Recorded for each host resolution. Note: Does not capture any delay spent queuing *before* initiating the host resolution (e.g., due to a max # of preconnects being in flight). blundell@chromium.org ryansturm@chromium.org sophiechang@chromium.org Measures the amount of time that a requested prefetch job spends queueing before being executed (e.g., due to a max # of prefetches being in flight). Recorded for each prefetch job. blundell@chromium.org ryansturm@chromium.org sophiechang@chromium.org Measures the length of the queue of prefetch jobs at the beginning of PrefetchManager processing this queue to execute jobs. Recorded each time that PrefetchManager processes the queue of pending jobs. nhiroki@chromium.org chrome-prerendering@chromium.org Measures time a PrerenderCommitDeferringCondition defers activation waiting to commit an ongoing mainframe prerender navigation. Logged every time a PrerenderCommitDeferringCondition defers navigation. After 2023/05, this metric is used with PrerenderTriggerType key and records even when PrerenderCommitDeferringCondition doesn't delay navigation as zero delay. Previously the metric was only used without the key and recorded only when PrerenderCommitDeferringCondition deferred navigation. cduvall@chromium.org jam@chromium.org Measures the amount of time the task to run {Method} was queued before running. Logged every time {Method} is run for a {FrameType} in NavigationURLLoaderImpl with a valid queue time. clamy@chromium.org nasko@chromium.org The time needed to commit a navigation once it is ready to commit. This is the time between ReadyToCommit and DidFinishNavigation (for a navigation that commits). Warning: this histogram was expired after M85 and brought back 2021-04-13; data may be missing. cduvall@chromium.org jam@chromium.org Measures the delay between when the navigation commit was sent by the browser to when it is received by the renderer. Recorded for every cross-document non-page activation navigation commit. cduvall@chromium.org jam@chromium.org Measures how long the navigation commit was waiting for the renderer process to start before it was able to receive the commit. Recorded for every cross-document non-page activation navigation commit which waits on a process start. cduvall@chromium.org jam@chromium.org Measures queue time for the navigation commit mojo task on the renderer side. Recorded for every cross-document non-page activation navigation commit. cduvall@chromium.org jam@chromium.org Measures time it takes to call NavigationControllerImpl::RendererDidNavigate. Recorded for each navigation that is not a same document navigation. Obsolete after 2022-10-21. All cancellation window ends within 10000ms. See UMA result: https://docs.google.com/document/d/1VNmvEVuaiNH3ypt6YfrYPsJJp8okCTYjooekarOiWN8/edit#heading=h.tlh3g7tofz2 rakina@chromium.org dcheng@chromium.org Measures the amount of time it takes from RendererCancellationThrottle::WillProcessResponse() to RendererCancellationThrottle::NavigationCancellationWindowEnded. Recorded for each navigation that gets deferred by RendererCancellationThrottle. alexmos@chromium.org lukasza@chromium.org Whether the navigation commits in a SiteInstance that requires a dedicated process. Logged at ready-to-commit time for every navigation excluding same-document navigations and errors. alexmos@chromium.org lukasza@chromium.org Whether the navigation commits in a SiteInstance that requires a dedicated process. Logged at ready-to-commit time for every navigation that commits with a HTTP or HTTPS URL scheme, excluding same-document navigations and errors. cduvall@chromium.org jam@chromium.org Measures the time RenderFrameHostImpl::SendCommitNavigation takes to run. Recorded every time the method executes. nasko@chromium.org csharrison@chromium.org The time delta between the start of a navigation and the time it is committed. Warning: this histogram was expired after M85 and brought back 2021-04-13; data may be missing. fergal@chromium.org rakina@chromium.org Records the combination of mainframe/subframe and what sudden termination disablers were present. This is recorded on every cross-document navigation. Currently only covers Unload. The SameOrigin variant only considers a frame to be same origin as the main frame if it can be reached through a chain of same-origin frames. So e.g. in a->b->a, the second a is not same-origin. cduvall@chromium.org jam@chromium.org Measures time a navigation throttle was deferred when on {Event}. Logged every time a throttle defers a navigation. cduvall@chromium.org jam@chromium.org Measures time a navigation throttle took to execute {Event}. Logged every time a throttle runs. nhiroki@chromium.org sreejakshetty@chromium.org chrome-prerendering@chromium.org The time needed to commit a navigation using prerender activation. This is the time from the beginning of NavigationStart to the end of DidCommitPageActivation. This metric is logged everytime prerender activation navigation commits. clamy@chromium.org nasko@chromium.org The time delta between the start of a navigation and the time it is ready to commit. Warning: this histogram was expired after M85 and brought back 2021-04-13; data may be missing. njeunje@chromium.org src/chrome/browser/tpcd/OWNERS The outcome from Third Party Cookies Deprecation Metadata component installation. This metric is recorded at most once for every new metadata version installed. Obsolete after 2022-06-30. rakina@chromium.org dcheng@chromium.org Records whether a speculative RenderFrame is live when UndoCommitNavigation is called. miketaylr@chromium.org potassium-katabolism@google.com The type of the user agent string value sent in the User-Agent header on a navigation request. The reduced user agent string is sent when User-Agent reduction feature kReduceUserAgentMinorVersion is enabled. This histogram is recorded when a NavigationRequest is constructed, prior to sending the request to the network stack. rakina@chromium.org altimin@chromium.org Logs inconsistencies between browser- vs renderer-calculated values of DidCommitProvisionalLoadParams which are detected in RenderFrameHostImpl's VerifyThatBrowserAndRendererCalculatedDidCommitParamsMatch(). This is used to trigger traces to be uploaded to analyze what happened in these navigations. cduvall@chromium.org jam@chromium.org Measures the amount of time the {Stage} stage takes in early navigation. Logged for any navigation that reaches the stage. meacer@chromium.org security-enamel@chromium.org Tracks events when the currently navigated domain name is a lookalike to one of the top 10K domains or a domain that the user interacted with, resulting in a navigation suggestion interstitial. Before M88, NavigationSuggestion.Event recorded a separate entry for each lookalike URL in a redirect chain. E.g. lookalike1.com -> site.com -> lookalike2.com recorded two events. This updated histogram only records an entry for the first or last URL in the redirect if any of those is a lookalike. meacer@chromium.org blundell@chromium.org security-enamel@chromium.org Records the time duration that PerformChecks() spent in calls to GetDomainInfo() before the navigation was ultimately allowed to proceed. Recorded only for navigations that LookalikeUrlNavigationThrottle::PerfomChecks() directly allows to proceed (i.e., not those that result in showing interstitials and/or digital asset manifest checks). meacer@chromium.org blundell@chromium.org security-enamel@chromium.org Records the time duration that PerformChecks() spent in calls to IsLookalikeUrl() before the navigation was ultimately allowed to proceed. Recorded only for navigations that LookalikeUrlNavigationThrottle::PerfomChecks() directly allows to proceed (i.e., not those that result in showing interstitials and/or digital asset manifest checks). meacer@chromium.org blundell@chromium.org security-enamel@chromium.org Records the time duration the navigation was deferred while PerformChecks() was executing before the navigation was ultimately allowed to proceed. Recorded only for navigations that LookalikeUrlNavigationThrottle::PerfomChecks() directly allows to proceed (i.e., not those that result in showing interstitials and/or digital asset manifest checks). meacer@chromium.org cduvall@chromium.org security-enamel@chromium.org Records the time duration the navigation was deferred while waiting for engaged sites data. Recorded whenever a navigation is deferred waiting for engaged sites. lingqi@chromium.org chrome-prerendering@chromium.org Tracks the prerender cancellations caused by inactive RenderFrameHosts' restrictions, recording the reason passed to RenderFrameHost::IsInactiveAndDisallowActivation calls. This metric is recored when a RenderFrameHost is going to perform some actions that are not allowed for a prerendering RenderFrameHost, such as showing context menu. At that time, the detailed reason will be passed to RenderFrameHost::IsInactiveAndDisallowActivation, which will cancel prerendering and record this metric. Note: This histogram does not track prerender activation behavior, but to analyze PrerenderHostFinalStatus::kInactivePageRestriction. Warning: this histogram was expired from 2023-03-01 to 2023-03-29; data may be missing. lingqi@chromium.org chrome-prerendering@google.com Breakdown metric for PrerenderActivationNavigationParamsMatch::kHttpRequestHeader. We are considering whether we should loosen this restriction, so this metric is added to figure out the usage of headers during prerender navigation and activation navigation. See https://crbug.com/1378921 for more information. When we are attempting to activate a prerendered page, we compare the prerendered page's NavigationRequest's headers with the incoming NavigationRequest's (called activation navigation). If they mismatch, PrerenderHost will post a task. The task scans the two headers, and will report a mismatching record if it detects any differences between them. It records the hashed number of a mismatching header, together with the mismatching reason: Missing in prerendering navigation, missing in activation navigation, or the values mismatch. Warning: this histogram was expired from 2023-01-31 to 2023-03-29; data may be missing. lingqi@chromium.org chrome-prerendering@google.com Recorded by WebViewImpl::ActivatePrerenderedPage when renderer process starts to ask the receiver end of the prerender activation IPC to process this signal, i.e., when this method is invoked. This metric is used to measure the delay of when renderer process receives the signal and when it can process this signal. Recorded on the main document only. nhiroki@chromium.org chrome-prerendering@google.com Records the mismatched parameters between the prerender initial navigation parameters and the prerender activation navigation parameters. Recorded by PrerenderHost in the browser process when comparing these two parameters. nhiroki@chromium.org chrome-prerendering@google.com Breakdown metric for PrerenderActivationNavigationParamsMatch::kTransition. When we are attempting to activate a prerendered page, we compare the prerendered page's NavigationRequest's ui::PageTransition with the incoming NavigationRequest's (called activation navigation). If they mismatch, this metric records the transition of the activation navigation in RecordPrerenderActivationTransition(). robertlin@chromium.org toyoshim@chromium.org chrome-prerendering@google.com The metrics for preload bookmark to understand the distribution of delay to press {ButtonType}. Recorded when the mouse {ButtonType} is pressed. robertlin@chromium.org toyoshim@chromium.org chrome-prerendering@google.com The metrics for preload boomark to understand the distribution of mouse hovering duration from {OriginType}. It records mouse hovering duration time when mouse leaves the bookmark button areas without using it as NotTaken, or when the bookmark is actually clicked as Taken. robertlin@chromium.org toyoshim@chromium.org chrome-prerendering@google.com This metric is to count the combination of bookmark bar triggering prerender's predictor's decision and result. Recorded on mouse leaving a bookmark button in the bookmark bar. robertlin@chromium.org toyoshim@chromium.org chrome-prerendering@google.com The metrics for preload bookmark to evaluate the ratio of mouseover and mousedown translating into full mouse click. lingqi@chromium.org nhiroki@chromium.org src/content/browser/preloading/prerender/OWNERS A breakdown metric for analyzing cross-origin redirection cases during embedder-triggered prerendering, Recorded when redirections were caused due to HTTP protocol upgrades. Note that for now it is not used for prerendering that are triggered by speculation rules. lingqi@chromium.org chrome-prerendering@google.com Records whether the search terms obtained via the search_terms_args are the same as the search terms extracted from the URLs. This is recorded when PrerenderManager attempts to start a new prerender. asamidoi@chromium.org chrome-prerendering@google.com Records the prediction status started by omnibox. In particular, this records whether they were used or not. It's recorded when omnibox-initiated navigation finishes. Consider it as a success when the prediction is correct and note that the activation of prerendering may fail. asamidoi@chromium.org chrome-prerendering@google.com Records the prediction status started by omnibox. In particular, this records whether they were used or not. It's recorded when omnibox-initiated navigation finishes. Consider it as a success when the prediction is correct and note that the activation of prerendering may fail. nhiroki@chromium.org toyoshim@chromium.org lingqi@chromium.org Mojo interfaces that cause the cancellation of prerendering. Recorded by MojoBinderPolicyApplier in the browser process once it receives the binding request of a kCancel Mojo interface. nhiroki@chromium.org toyoshim@chromium.org lingqi@chromium.org This histogram tracks the interfaces that Prerender.Experimental.PrerenderCancelledInterface fails to track. It is needed because: * Embedders can set their own policies, so Prerender2 cannot map all of them to enums. * Channel-associated interfaces' policies are set to kCancel implicitly. It's hard to track all of them, especially the newly added channel-associated interfaces. This sparse histogram allows Prerender2 to record all of these interfaces separately. It is recored by MojoBinderPolicyApplier in the browser process once it receives the binding request of a kCancel Mojo interface and cannot find an accurate enum type for this interface. lingqi@chromium.org nhiroki@chromium.org src/content/browser/preloading/prerender/OWNERS A breakdown metric for analyzing cross-origin redirection cases during embedder-triggered prerendering. Recorded when the embedder-triggered prerendering was redirected to another origin that differs from the initial one. The cases are encoded into 3 bits(scheme mismatch, host mismatch, port mismatch). Note that for now it is not used for prerendering that are triggered by speculation rules. nhiroki@chromium.org toyoshim@chromium.org lingqi@chromium.org asamidoi@chromium.org Final status for a prerendering attempt. Recorded by PrerenderHost or PrerenderHostRegistry in the browser process when the attempt finishes. lingqi@chromium.org chrome-prerendering@google.com Net error code is recorded by PrerenderCancellationReason when a prerender host is canceled due to kDidFailLoad. This metric is used to monitor whether preload cache intercepting logic causes extra page loading errors. Similar to PageLoad.Internal.Prerender2.ActivatedPageLoaderStatus{PrerenderTriggerType}, but used to track the loading status of not activated prerendered pages. taiyo@chromium.org chrome-prerendering@google.com Records the number of eventually received speculation rules prerender triggers with eagerness per primary page changed, classified with their eagerness. This is coutend via started_prerenders_ on PrerendererImpl and recorded when primary page is changed and PrerendererImpl::CancelStartedPrerenders is called. Note that this metric only records where PrerenderTriggerType is SpeculationRule and SpeculationRuleFromIsolatedWorld. lingqi@chromium.org chrome-prerendering@google.com Recorded by RecordBlockedByClientResourceType when prerender is cancelled due to the restriction that client blocks a resource loading. lingqi@chromium.org chrome-prerendering@google.com PrerenderManager records the duration period from the time to start prerendering with the search hints to the time to navigate the search hints. This duration is recorded when it finds the search hints predicts correctly, e.g. users do search and results in activating the prerendered page, or users do saerch the prerender hints but the prerendered page has been destroyed due to expiration. |====== HitFinishedSearchResultLifeTime=======| @ Timestamp X ------------------------------- @ Timestamp Y or |====== HitFinishedSearchResultLifeTime=============| @ Timestamp X ------------------------------------- @ Timestamp Z Where: * Timestamp X: Chrome receives the first prerender hints for a search term A. * Timestamp Y: User selects the search term A. * Timestamp Z: Timestamp X + Fixed period T. HitFinishedSearchResultLifeTime = min(Timestamp Y, Timestamp Z) - Timestamp X = min(Timestamp Y - Timestamp X, T). It aims to: 1. Track the prerenders which were canceled due to expiration(Fixed period T). 2. Gain the understanding of the duration between the moment when browser receives the first prerender hint and the moment when the hint is selected. This data will be used to determine the threshold of deciding whether to reuse a prefetched response or to resend a prefetch request. lingqi@chromium.org chrome-prerendering@google.com Recorded by StreamingSearchPrefetchURLLoader in its destructor. This instance is created per (non-duplicated) prefetch attempt. The destructor runs upon: - Case 1: A prefetched response is deleted upon expiration or network error. - Case 2: A prefetched response deletes itself after finishing serving to navigations. This will be executed asynchronously. See comments in StreamingSearchPrefetchURLLoader for more information. Indicates the number of prerendering DSE navigation that one prefetched response served to. In most cases, it should record 0 (which means the loader does not serve to any prerendering navigations) or 1 (served to one prerender). And we will track the count that is greater than 2 to determine whether the loader should be designed to target multiple serving destinations. This number should be quite small (0 or 1 in most cases), so the count is capped at 9 and put into 10 buckets, from 0 to 9. ryansturm@chromium.org tbansal@chromium.org Final status for prerender pages - either success, or why it was canceled. hajimehoshi@chromium.org jkarlin@chromium.org kouhei@chromium.org Number of bytes transferred on the network for URLRequests (not including HTTP/TLS/TCP/IP overhead). Reported on event of a PrerenderContents deletion. Includes prerender bytes. Bytes are only counted when prerendering is enabled and not in a control group. The sum of the distribution for a single user represents all of that user's network transfers for resource for that time period while prerendering was enabled. hajimehoshi@chromium.org jkarlin@chromium.org kouhei@chromium.org Number of bytes transferred on the network for URLRequests (not including HTTP/TLS/TCP/IP overhead) for a prerender that was not used. All nostate-prefetch bytes are currently counted as wasted because it is hard to track byte use in HTTP cache. droger@chromium.org mattcary@chromium.org pasko@chromium.org Length of the redirect chain for main resources loaded by NoStatePrefetch. Recorded when the final response in the chain is received. droger@chromium.org mattcary@chromium.org pasko@chromium.org Type of responses received by NoStatePrefetch, distinguishing cacheable resources from no-store resources, and main resources from sub-resources. Recorded when a response is received, including on each redirect. droger@chromium.org mattcary@chromium.org pasko@chromium.org Length of the redirect chain for sub-resources loaded by NoStatePrefetch. Recorded when the final response in the chain is received. gambard@chromium.org justincohen@chromium.org Whether the load was completed when the pre-render was used. If the prerender is cancelled, this is not logged. Only on iOS. justincohen@chromium.org Whether or not a successful prerender happens on a NTP with no history. justincohen@chromium.org The last comitted index before a successful preload is committed. Recorded only on iOS. ryansturm@chromium.org tbansal@chromium.org The number of sessions that have at least X successful prerenders. Recorded only on iOS since 2017-09. gambard@chromium.org justincohen@chromium.org This is the time from when a prerendered page begins to load to when it is swapped in as the main page load or to when the pre-loaded page is fully loaded, whichever came first. Recorded when the swap occurs, only on iOS. pasko@chromium.org A boolean that indicates how often we fail to delete an old prerendered tab before the timeout.