tools/metrics/histograms/histograms_xml/navigation/histograms.xml

<!--
Copyright 2020 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<!--
This file is used to generate a comprehensive list of Navigation histograms
along with a detailed description for each histogram.

For best practices on writing histogram descriptions, see
https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histograms/README.md

Please send CLs to chromium-metrics-reviews@google.com rather than to specific
individuals. These CLs will be automatically reassigned to a reviewer within
about 5 minutes. This approach helps the metrics team to load-balance incoming
reviews. Googlers can read more about this at go/gwsq-gerrit.
-->

<histogram-configuration>

<histograms>

<histogram name="BackForwardCache.AllSites.EvictedAfterDocumentRestoredReason"
    enum="BackForwardCacheEvictedAfterDocumentRestoredReason"
    expires_after="2021-10-01">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="BackForwardCache.AllSites.HistoryNavigationOutcome"
    enum="BackForwardCacheHistoryNavigationOutcome" expires_after="2021-06-20">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.AllSites.HistoryNavigationOutcome.BlocklistedFeature"
    enum="WebSchedulerTrackedFeature" expires_after="2021-06-27">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.AllSites.HistoryNavigationOutcome.BrowsingInstanceNotSwappedReason"
    enum="BackForwardCacheBrowsingInstanceNotSwappedReason"
    expires_after="2021-06-13">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    When navigating back to a page in the session history and the
    BackForwardCache wasn't used because of the related browsing instances, 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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.AllSites.HistoryNavigationOutcome.DisabledForRenderFrameHostReason"
    enum="BackForwardCacheDisabledForRenderFrameHostReason"
    expires_after="2021-10-01">
  <owner>carlscab@chromium.org</owner>
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    For history navigations, records the reasons passed to
    BackForwardCache::DisableForRenderFrameHost calls. These reasons are
    specified as strings, so this histograms contains their hashes computed as
    base::HashMetricName.

    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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.AllSites.HistoryNavigationOutcome.NotRestoredReason"
    enum="BackForwardCacheNotRestoredReason" expires_after="2021-06-13">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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 whether back-forward cache is
    enabled or not.
  </summary>
</histogram>

<histogram name="BackForwardCache.EvictedAfterDocumentRestoredReason"
    enum="BackForwardCacheEvictedAfterDocumentRestoredReason"
    expires_after="2021-06-13">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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).
  </summary>
</histogram>

<histogram name="BackForwardCache.Eviction.TimeUntilProcessKilled" units="ms"
    expires_after="2021-10-01">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.Experimental.UnexpectedIPCMessagePostedToCachedFrame.MethodHash"
    enum="MojoInterfaceName" expires_after="2021-05-30">
  <owner>hbolaria@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.Experimental.UnexpectedIPCMessagePostedToCachedFrame.TimeUntilIPCReceived"
    units="ms" expires_after="2021-05-30">
  <owner>hbolaria@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="BackForwardCache.HistoryNavigationOutcome"
    enum="BackForwardCacheHistoryNavigationOutcome" expires_after="2021-10-01">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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).
  </summary>
</histogram>

<histogram name="BackForwardCache.HistoryNavigationOutcome.BlocklistedFeature"
    enum="WebSchedulerTrackedFeature" expires_after="2021-06-13">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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).
  </summary>
</histogram>

<histogram
    name="BackForwardCache.HistoryNavigationOutcome.BrowsingInstanceNotSwappedReason"
    enum="BackForwardCacheBrowsingInstanceNotSwappedReason"
    expires_after="2021-06-13">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    When navigating back to a page in the session history and the
    BackForwardCache wasn't used because of the related browsing instances, 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).
  </summary>
</histogram>

<histogram
    name="BackForwardCache.HistoryNavigationOutcome.DisabledForRenderFrameHostReason"
    enum="BackForwardCacheDisabledForRenderFrameHostReason"
    expires_after="2021-06-13">
  <owner>carlscab@chromium.org</owner>
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    For history navigations, records the reasons passed to
    BackForwardCache::DisableForRenderFrameHost calls. These reasons are
    specified as strings, so this histograms contains their hashes computed as
    base::HashMetricName.

    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 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).
  </summary>
</histogram>

<histogram name="BackForwardCache.HistoryNavigationOutcome.NotRestoredReason"
    enum="BackForwardCacheNotRestoredReason" expires_after="2021-06-13">
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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).
  </summary>
</histogram>

<histogram name="BackForwardCache.MainFrameHasPageshowListenersOnRestore"
    enum="BooleanPresent" expires_after="M82">
  <owner>altimin@chromium.org</owner>
  <owner>hajimehoshi@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.ProactiveSameSiteBISwap.EligibilityDuringCommit"
    enum="BackForwardCacheEligibilityDuringCommit" expires_after="M88">
  <owner>rakina@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Records whether a page where we did a same-site proactive BrowsingInstance
    swap on (with the intention on storing it in the back-forward cache later)
    is still eligible for back-forward cache when swapping out the old page
    during navigation commit. Recorded when we have just finished committing the
    new page on the renderer side, and during the commit of the new page in the
    browser side.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.ProactiveSameSiteBISwap.SameSiteNavigationDidSwap"
    enum="BackForwardCacheSameSiteNavigationDidSwap" expires_after="M88">
  <owner>rakina@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Records whether we did a same-site proactive BrowsingInstance swap or not
    for a same-site cross-document navigation. Recorded when we are committing
    the navigation.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.ProactiveSameSiteBISwap.UnloadRunsAfterCommit"
    enum="BackForwardCacheUnloadRunsAfterCommit" expires_after="M88">
  <owner>rakina@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Records whether a page where we did a same-site proactive BrowsingInstance
    swap on (with the intention on storing it in the back-forward cache later)
    is no longer eligible for back-forward cache after the navigation committed
    and the page has unload handlers that will run after commit, which is a
    web-observable behavior change for same-site navigations. Recorded when we
    have just finished committing the new page on the renderer side, and during
    the commit of the new page in the browser side.
  </summary>
</histogram>

<histogram name="BackForwardCache.ReloadsAfterHistoryNavigation"
    enum="BackForwardCacheReloadsAfterHistoryNavigation"
    expires_after="2021-10-01">
  <owner>sreejakshetty@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Records the number of reloads after a history navigation both for the cases
    when page is served and not served from back-forward cache.

    This is recorded when navigation is committed, only for the domains which
    are in the scope of back-forward cache experiment and they are of same
    NavigationEntry (e.g. back and reload in different tab do not count).
  </summary>
</histogram>

<histogram name="BackForwardCache.ReloadsAndHistoryNavigations"
    enum="BackForwardCacheReloadsAndHistoryNavigations"
    expires_after="2021-10-01">
  <owner>sreejakshetty@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Records the total number of history navigations along with the number of
    reloads if the previous navigation was a history one.

    This is recorded when navigation is committed, only for the domains which
    are in the scope of back-forward cache experiment.
  </summary>
</histogram>

<histogram name="BackForwardCache.Restore.DisableEvictionDelay" units="ms"
    expires_after="2021-10-01">
  <owner>carlscab@google.com</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Delay introduced by the IPC round trips to disable eviction in all the
    renderers of a page stored in the back-forward cache. That is, the interval
    of time between sending an SetPageLifecycleState IPC to each renderer and
    receiving all the responses.

    Recorded on reception of the last ACK reply. We added this histogram to
    measure the impact of this extra round trip to the renderer when restoring a
    page from the back-forward cache.
  </summary>
</histogram>

<histogram name="BackForwardCache.Restore.NavigationToFirstPaint" units="ms"
    expires_after="2021-10-01">
  <owner>sreejakshetty@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="BackForwardCache.SameSite.ActionAfterPagehide2"
    enum="BackForwardCacheActionAfterPagehide" expires_after="M88">
  <owner>rakina@chromium.org</owner>
  <owner>altimin@chromium.org</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    Records occurences of certain actions triggered by script running on a page
    after the pagehide event gets dispatched in the page, which might be
    possible if we dispatch the pagehide event without unloading/freezing the
    page (only happens when we're doing a same-site navigation and we did a
    proactive BrowsingInstance swap but we're reusing the old page's process).

    Note: We will only track actions that might affect the user after we've
    navigated away from the old page, such as modifications to storage,
    navigations, or sending/receiving postMessage.

    Note 2: We will not track actions taken when the unload event is currently
    in progress, which means the page is not actually stored in the back-forward
    cache and the actions are expected to happen after pagehide.
  </summary>
</histogram>

<histogram
    name="BackForwardCache.UnexpectedRendererToBrowserMessage.InterfaceName"
    enum="MojoInterfaceName" expires_after="2021-05-09">
  <owner>carlscab@google.com</owner>
  <owner>bfcache-dev@chromium.org</owner>
  <summary>
    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
    &quot;message_handling_when_cached&quot;.

    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).
  </summary>
</histogram>

<histogram name="Navigation.BackForward.AllBackTargetsSkippable" enum="Boolean"
    expires_after="2019-12-31">
  <owner>shivanisha@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    This metric logs true if all the previous entries are marked to be skipped
    on back/forward button via the history manipulation intervention. This is
    logged when back button is pressed (see crbug.com/907167). The goal of the
    intervention is to intervene against pages that manipulate browser history
    such that the user is not able to use the back button to go to the previous
    site they interacted with.
  </summary>
</histogram>

<histogram name="Navigation.BackForward.BackTargetSkipped" units="units"
    expires_after="M85">
  <owner>shivanisha@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    This metric counts the number of entries the history manipulation
    intervention would have skipped when the user presses the back button (see
    crbug.com/907167). The goal of the intervention is to intervene against
    pages that manipulate browser history such that the user is not able to use
    the back button to go to the previous site they interacted with.
  </summary>
</histogram>

<histogram name="Navigation.BackForward.CacheFlags" enum="NavigationCacheEnum"
    expires_after="M85">
  <owner>clamy@chromium.org</owner>
  <summary>The cache flags set on back-forward navigations.</summary>
</histogram>

<histogram name="Navigation.BackForward.ForwardTargetSkipped" units="units"
    expires_after="M85">
  <owner>shivanisha@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    This metric counts the number of entries the history manipulation
    intervention would have skipped when the user presses the forward button
    (see crbug.com/907167). The goal of the intervention is to intervene against
    pages that manipulate browser history such that the user is not able to use
    the back button to go to the previous site they interacted with.
  </summary>
</histogram>

<histogram name="Navigation.BackForward.NavigatingToEntryMarkedToBeSkipped"
    enum="Boolean" expires_after="2019-12-31">
  <owner>shivanisha@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.BackForward.SetShouldSkipOnBackForwardUI"
    enum="Boolean" expires_after="M85">
  <owner>shivanisha@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    Whether an entry in the back-forward list is marked to be skipped on
    subsequent back/forward button clicks as part of the history manipulation
    intervention. This is logged when the entry is navigated away from. The goal
    is to intervene against pages that manipulate browser history such that the
    user is not able to use the back button to go to the previous site they
    interacted with.
  </summary>
</histogram>

<histogram name="Navigation.BackForward.WasCached"
    enum="NavigationWasServedFromCache" expires_after="M85">
  <owner>clamy@chromium.org</owner>
  <summary>Whether the back-forward navigation was served from cache.</summary>
</histogram>

<histogram name="Navigation.ClearSiteData.Duration" units="ms"
    expires_after="M77">
  <owner>msramek@chromium.org</owner>
  <summary>
    Recorded when a navigation is deferred while clearing site data. Indicates
    how much time the clearing took.
  </summary>
</histogram>

<histogram name="Navigation.ClearSiteData.Parameters"
    enum="ClearSiteDataParameters" expires_after="M77">
  <owner>msramek@chromium.org</owner>
  <summary>
    The parameters of the Clear-Site-Data header. Recorded when the header is
    successfully parsed.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.ErrorCode" enum="NetErrorCodes"
    expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logs the error code for each navigation commit timeout. This will be used to
    debug http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.IsMainFrame" enum="BooleanMainFrame"
    expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logs whether this was a main frame navigation for each navigation commit
    timeout. This will be used to debug http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.IsRendererProcessReady"
    enum="BooleanReady" expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logged with the status of the renderer process for each navigation commit
    timeout. This will be used to debug http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.NetworkServiceAvailability"
    enum="NetworkServiceAvailability" expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logged with the status of the network service for each navigation commit
    timeout. This will be used to debug http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.NetworkServiceLastCrashTime"
    units="ms" expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logged with the time since the last network service crash if available for
    each navigation commit timeout. This will be used to debug
    http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.NetworkServicePingTime" units="ms"
    expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logs the time it takes to make a round trip call to the network service for
    each navigation commit timeout. This will be used to debug
    http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.CommitTimeout.Scheme" enum="NavigationURLScheme"
    expires_after="M82">
  <owner>cduvall@chromium.org</owner>
  <owner>cmumford@chromium.org</owner>
  <summary>
    Logged with the navigation URL scheme for each navigation commit timeout.
    This will be used to debug http://crbug.com/934317.
  </summary>
</histogram>

<histogram name="Navigation.DownloadPolicy.LogArbitraryPolicyPerDownload"
    enum="NavigationDownloadPolicy" expires_after="2020-11-01">
  <owner>csharrison@chromium.org</owner>
  <owner>yaoxia@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.DownloadPolicy.LogPerPolicyApplied"
    enum="NavigationDownloadPolicy" expires_after="2020-11-01">
  <owner>csharrison@chromium.org</owner>
  <owner>yaoxia@chromium.org</owner>
  <summary>
    When a navigation results in a download, for each download policy applied to
    that navigation, logs the policy.
  </summary>
</histogram>

<histogram name="Navigation.EngagementTime.HTTP" units="ms" expires_after="M94">
  <owner>estark@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    The amount of time that an HTTP page was in the foreground. Recorded on
    every page close/transition.
  </summary>
</histogram>

<histogram name="Navigation.EngagementTime.HTTPS" units="ms"
    expires_after="M94">
  <owner>estark@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    The amount of time that an HTTPS page was in the foreground. Recorded on
    every page close/transition.
  </summary>
</histogram>

<histogram name="Navigation.EngagementTime.Ratio" units="%" expires_after="M89">
  <owner>estark@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    The percentage of time that HTTPS pages were in the foreground, as compared
    to total foreground time. Recorded whenever user metrics are uploaded.
  </summary>
</histogram>

<histogram name="Navigation.Home.IsChromeInternal" enum="Boolean"
    expires_after="never">
<!-- expires-never: part of top-line metric (internal: go/chrome-browser-nsm) -->

  <owner>mpearson@chromium.org</owner>
  <owner>amaralp@chromium.org</owner>
  <owner>chrome-analysis-team@google.com</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.IOSNullContextInDidFailProvisionalNavigation"
    enum="Boolean" expires_after="M85">
  <owner>ajuma@chromium.org</owner>
  <owner>eugenebut@chromium.org</owner>
  <summary>
    Logged when NavigationContext is null inside -[WKNavigationDelegate
    webView:didFailProvisionalNavigation]. If Chrome stopped logging this metric
    it means that it is now safe to remove workaround for
    https://bugs.webkit.org/show_bug.cgi?id=198794.
  </summary>
</histogram>

<histogram name="Navigation.IsLockedProcess" enum="NavigationIsLockedProcess"
    expires_after="2021-12-21">
  <owner>alexmos@chromium.org</owner>
  <owner>lukasza@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.IsLockedProcess.HTTPOrHTTPS"
    enum="NavigationIsLockedProcess" expires_after="2021-12-21">
  <owner>alexmos@chromium.org</owner>
  <owner>lukasza@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.IsSameBrowsingInstance"
    enum="NavigationIsSameBrowsingInstance" expires_after="2021-05-09">
  <owner>arthursonzogni@chromium.org</owner>
  <owner>clamy@chromium.org</owner>
  <owner>nasko@chromium.org</owner>
  <summary>
    Whether a main frame navigation led to a change of BrowsingInstance or not.
  </summary>
</histogram>

<histogram name="Navigation.IsSameProcess" enum="NavigationIsSameProcess"
    expires_after="M85">
  <owner>clamy@chromium.org</owner>
  <owner>nasko@chromium.org</owner>
  <summary>Whether the navigation led to a change of process or not.</summary>
</histogram>

<histogram name="Navigation.IsSameSiteInstance"
    enum="NavigationIsSameSiteInstance" expires_after="2021-07-11">
  <owner>arthursonzogni@chromium.org</owner>
  <owner>clamy@chromium.org</owner>
  <owner>nasko@chromium.org</owner>
  <summary>
    Whether the navigation led to a change of SiteInstance or not.
  </summary>
</histogram>

<histogram name="Navigation.LoadIfNecessaryType"
    enum="NavigationNeedsReloadType" expires_after="never">
<!-- expires-never: Generally useful metric on Android that tracks number of automatic tab reloads and their cause.  -->

  <owner>boliu@chromium.org</owner>
  <owner>alexmos@chromium.org</owner>
  <owner>src/base/android/OWNERS</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.MainFrame.FrameCount" units="frames"
    expires_after="2021-08-01">
  <owner>michaelpg@chromium.org</owner>
  <owner>yilkal@chromium.org</owner>
  <owner>cros-families-eng@google.com</owner>
  <summary>
    The number of frames that are present in a WebContents. Recorded once when
    the main frame finishes loading.
  </summary>
</histogram>

<histogram name="Navigation.MainFrame.MaxFrameCount" units="frames"
    expires_after="2021-08-01">
  <owner>michaelpg@chromium.org</owner>
  <owner>yilkal@chromium.org</owner>
  <owner>cros-families-eng@google.com</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.MainFrame.SiteEngagementLevel"
    enum="SiteEngagementLevel" expires_after="2021-06-06">
  <owner>meacer@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    Site engagement level of the URL of the top frame of a navigation. Only
    counts HTTP or HTTPS URLs and ignores downloads.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameFormSubmission.SiteEngagementLevel"
    enum="SiteEngagementLevel" expires_after="2021-04-04">
  <owner>meacer@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    Site engagement level of the URL of the top frame of a form submission. This
    is a subset of Navigation.MainFrame.SiteEngagementLevel.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameHasRTLDomain2" enum="Boolean"
    expires_after="M92">
  <owner>cthomp@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    Whether the main-frame navigation was to a URL with an RTL domain name. This
    is only recorded for finished navigations and not attempts.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameHasRTLDomainDifferentPage2" enum="Boolean"
    expires_after="M92">
  <owner>cthomp@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameProfileType2" enum="BrowserProfileType"
    expires_after="2021-06-01">
  <owner>rhalavati@chromium.org</owner>
  <owner>chrome-privacy-core@google.com</owner>
  <summary>
    The browser profile type for each main-frame navigation, recorded after
    navigation completion, including NTP.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameScheme2" enum="NavigationScheme"
    expires_after="2021-06-01">
  <owner>elawrence@chromium.org</owner>
  <owner>estark@chromium.org</owner>
  <summary>
    The scheme of the URL for each main-frame navigation. This is only recorded
    for finished navigations and not attempts.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameSchemeDifferentPage2"
    enum="NavigationScheme" expires_after="2021-06-01">
  <owner>elawrence@chromium.org</owner>
  <owner>estark@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameSchemeDifferentPageOTR2"
    enum="NavigationScheme" expires_after="2021-06-01">
  <owner>elawrence@chromium.org</owner>
  <owner>estark@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.MainFrameSchemeOTR2" enum="NavigationScheme"
    expires_after="2021-06-01">
  <owner>elawrence@chromium.org</owner>
  <owner>estark@chromium.org</owner>
  <summary>
    The scheme of the URL for each main-frame navigation while in incognito.
    This is only recorded for finished navigations and not attempts.
  </summary>
</histogram>

<histogram name="Navigation.NavigationURLLoaderImplIOPostTime"
    units="microseconds" expires_after="M79">
  <owner>jam@chromium.org</owner>
  <owner>kinuko@chromium.org</owner>
  <summary>
    The sum of all the times spent posting tasks between the UI and IO threads
    inside NavigationURLLoaderImpl. Recorded when each frame navigation gets the
    response.

    Note: This metric drops reports on clients with low-resolution clocks, which
    means these reports will be biased against a portion of the population on
    Windows. See Windows.HasHighResolutionTimeTicks for the affected sample.
  </summary>
</histogram>

<histogram name="Navigation.OnBeforeUnloadOverheadTime" units="ms"
    expires_after="M89">
  <owner>clamy@chromium.org</owner>
  <owner>nasko@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.OnReceiveResponseToOnStartLoadingResponseBody"
    units="ms" expires_after="M85">
  <owner>falken@chromium.org</owner>
  <owner>chrome-loading@google.com</owner>
  <summary>
    Time between the two messages OnReceiveResponse and
    OnStartLoadingResponseBody as observed by the browser process during a
    navigation by NavigationURLLoader::URLLoaderRequestController. The idea is
    to see whether there is a performance cost in having two separate messages,
    as the plan is to combine them into one.
  </summary>
</histogram>

<histogram name="Navigation.ReadyToCommitUntilCommit2" units="ms"
    expires_after="M85">
  <owner>clamy@chromium.org</owner>
  <owner>nasko@chromium.org</owner>
  <summary>
    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).
  </summary>
</histogram>

<histogram name="Navigation.RequiresDedicatedProcess"
    enum="NavigationRequiresDedicatedProcess" expires_after="2021-12-21">
  <owner>alexmos@chromium.org</owner>
  <owner>lukasza@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.RequiresDedicatedProcess.HTTPOrHTTPS"
    enum="NavigationRequiresDedicatedProcess" expires_after="2021-12-21">
  <owner>alexmos@chromium.org</owner>
  <owner>lukasza@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="Navigation.SecureSchemeHasSSLStatus" enum="BooleanPresent"
    expires_after="M85">
  <owner>jam@chromium.org</owner>
  <summary>
    True counts the events when a https URL commits with a SSL certificate.
    False is when the certificate is missing. This should be at 100%, anything
    less is probably a bug.
  </summary>
</histogram>

<histogram name="Navigation.StartToCommit" units="ms" expires_after="M85">
  <owner>nasko@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    The time delta between the start of a navigation and the time it is
    committed.
  </summary>
</histogram>

<histogram name="Navigation.TimeToReadyToCommit2" units="ms"
    expires_after="M85">
  <owner>clamy@chromium.org</owner>
  <owner>nasko@chromium.org</owner>
  <summary>
    The time delta between the start of a navigation and the time it is ready to
    commit.
  </summary>
</histogram>

<histogram name="Navigation.TimeToURLJobStart" units="ms" expires_after="M85">
  <obsolete>
    Removed from code in M89 (Nov 2020), after expiring in M85.
  </obsolete>
  <owner>carlosk@chromium.org</owner>
  <summary>
    Time between the start of a browser-started navigation request and the
    reception of a corresponding ResourceRequest in the network stack.
  </summary>
</histogram>

<histogram
    name="Navigation.URLLoaderNetworkService.OnCompleteCertificateChainsSize"
    units="KB" expires_after="M78">
  <owner>estark@chromium.org</owner>
  <summary>
    When the navigation URL loader receives an OnComplete message from the
    network service that contains certificate chains, this histogram records the
    size in KB of those pickled certificate chains. This histogram is recorded
    by the navigation URLLoader for navigations that fetch from network, for
    every request which contains an SSLInfo in its OnComplete notification.
  </summary>
</histogram>

<histogram name="Navigation.URLLoaderNetworkService.OnCompleteHasSSLInfo"
    enum="BooleanPresent" expires_after="M77">
  <owner>estark@chromium.org</owner>
  <summary>
    Whether the network service's OnComplete message to the navigation URL
    loader contains an SSLInfo, which should only be present for main-frame
    requests with certificate errors. This histogram is recorded for every
    request completion by the navigation URL loader that fetches from network.
  </summary>
</histogram>

<histogram base="true" name="NavigationPredictor.ActionTaken"
    enum="NavigationPredictorActionTaken" expires_after="M85">
  <owner>tbansal@chromium.org</owner>
  <summary>
    Tracks action taken by navigation predictor. Recorded at the time of page
    load.
  </summary>
</histogram>

<histogram base="true" name="NavigationPredictor.CountOfStartedPrerenders"
    units="count" expires_after="M85">
  <owner>tbansal@chromium.org</owner>
  <owner>ryansturm@chromium.org</owner>
  <summary>
    Reports data about the clicked link with regards to whether it was
    prerendered by the Navigation Predictor. Recorded when the page is navigated
    away from.
  </summary>
</histogram>

<histogram base="true" name="NavigationPredictor.CountOfURLsAboveThreshold"
    units="count" expires_after="M85">
  <owner>tbansal@chromium.org</owner>
  <owner>ryansturm@chromium.org</owner>
  <summary>
    Reports data about the clicked link with regards to whether it was
    prerendered by the Navigation Predictor. Recorded when the page is navigated
    away from.
  </summary>
</histogram>

<histogram base="true" name="NavigationPredictor.CountOfURLsInPredictedSet"
    units="count" expires_after="M89">
  <owner>tbansal@chromium.org</owner>
  <owner>ryansturm@chromium.org</owner>
  <summary>
    Reports data about the clicked link with regards to whether it was
    prerendered by the Navigation Predictor. Recorded when the page is navigated
    away from.
  </summary>
</histogram>

<histogram name="NavigationPredictor.ExternalAndroidApp.CountPredictedURLs"
    units="Count" expires_after="2021-07-26">
  <owner>sophiechang@chromium.org</owner>
  <owner>tbansal@chromium.org</owner>
  <summary>
    Count of likely URLs for the next navigation as reported by an external
    Android app via mayLaunchUrl() Android API. Recorded at the time the
    prediction was received by Chrome.
  </summary>
</histogram>

<histogram name="NavigationPredictor.IsPubliclyRoutable" enum="Boolean"
    expires_after="2021-06-20">
  <owner>tbansal@chromium.org</owner>
  <owner>ryansturm@chromium.org</owner>
  <summary>
    Set to true if the IP address of the origin of the main frame URL is
    publically routable. Recorded everytime a preconnect attempt is made by the
    navigation predictor.
  </summary>
</histogram>

<histogram base="true" name="NavigationPredictor.LinkClickedPrerenderResult"
    enum="NavigationPredictorLinkClickedPrerenderResult" expires_after="M85">
  <owner>ryansturm@chromium.org</owner>
  <owner>tbansal@chromium.org</owner>
  <summary>
    Reports data about the clicked link with regards to whether it was
    prerendered by the Navigation Predictor. Recorded when the user clicks a
    link.
  </summary>
</histogram>

<histogram
    name="NavigationPredictor.SearchEnginePreconnector.IsBrowserAppLikelyInForeground"
    enum="BooleanForeground" expires_after="M95">
  <owner>tbansal@chromium.org</owner>
  <owner>ryansturm@chromium.org</owner>
  <summary>
    Reports if the browser app was in foreground when a preconnect attempt was
    made to the default search engine.
  </summary>
</histogram>

<histogram name="NavigationSuggestion.Event" enum="NavigationSuggestionEvent"
    expires_after="M89">
  <obsolete>
    Replaced with NavigationSuggestion.Event2 on 2020/10 because of
    crbug.com/1136296.
  </obsolete>
  <owner>meacer@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    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.
  </summary>
</histogram>

<histogram name="NavigationSuggestion.Event2" enum="NavigationSuggestionEvent"
    expires_after="2021-06-20">
  <owner>meacer@chromium.org</owner>
  <owner>security-enamel@chromium.org</owner>
  <summary>
    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 -&gt; site.com -&gt;
    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.
  </summary>
</histogram>

</histograms>

</histogram-configuration>