lizeb@chromium.org pasko@chromium.org lizeb@chromium.org pasko@chromium.org jinsukkiim@google.com clank-app-team@google.com Records the variant of adaptive toolbar button when its fallback UI was clicked. The fallback UI becomes available in the form of overflow menu or Message UI when when the button itself was hidden due to various reasons. Recorded when the user click the fallback UI. Android only. jinsukkiim@google.com clank-app-team@google.com Records the ranking of the toolbar button variant picked up for display. It will be either 0 or 1. Recorded when the suggested list of variants are checked in the filtering process. Android only. jinsukkiim@google.com clank-app-team@google.com Records the variant of adaptive toolbar button for which fallback indicator (menu dot) is clicked. Recorded when the overflow menu icon is clicked when the indicator is visible. Android only. jinsukkiim@google.com clank-app-team@google.com Records the variant of adaptive toolbar button for which fallback indicator (menu dot) is shown. Recorded when the indicator is shown on the overflow menu icon. Android only. jinsukkiim@google.com clank-app-team@google.com Records the reason the Adaptive toolbar button was hidden in Custom Tabs. Recorded when the toolbar layout is initialized/updated, or adaptive toolbar button is updated on the toolbar. Android only. jinsukkiim@google.com clank-app-team@google.com Records the variant of adaptive toolbar button shown on the CCT toolbar. Recorded when the visibility of the button is determined. Android only. hattorij@google.com ishitatsuyuki@google.com lt-performance@google.com Records the version of android_browser_helper during Custom Tabs startup. sinansahin@google.com chrome-connective-tissue@google.com Records the time it took to complete the DAL verification since the auth flow in the Auth Tab was completed, i.e. navigation to the redirect_uri happened. Unlike CustomTabs.AuthTab.TimeToDalVerification.SinceNativeInit, this is only recorded when the verification isn't done before the auth flow completion. Recorded when OriginVerifier returns a result. Android only. sinansahin@google.com chrome-connective-tissue@google.com Records the total time it took to complete the DAL verification, regardless of the success status, when OriginVerifier returns a result. Android only. sinansahin@google.com chrome-connective-tissue@google.com A bit field with each bit representing the presence of a potential OAuth query param in the URL. Recorded when the Custom Tab receives and handles the initial intent. Android only. Available bit flags: 0b00001: client_id, 0b00010: redirect_uri, 0b00100: response_type, 0b01000: scope, 0b10000: state jinsukkim@chromium.org twellington@chromium.org cct-team@google.com Android: Duration in milliseconds of a custom tab session (between onResume and onPause). This is logged for the sessions closed automatically without user intervention. Sessions closed by user input (back press/close button) will not be logged. Note that there can be user inputs that go undetected by the logic. So the histogram can contain false positives i.e. session closed by user but regarded as auto-closed. jinsukkim@chromium.org chrome-connective-tissue@google.com For every CCT launch, Chrome will start an async task in the background checking the last time branding is shown for the client app. Each client app is identified with a unique string. It was initially (and preferably) its package name but is extended to be of any text string from the intent's referrer if the package name is unavailable. An empty string is regarded as invalid id. Record the type of the id for a given CCT when the async task is finished. Record for Android CCT only. yusufo@chromium.org Android: AppId declared by the launching application in EXTRA_APPLICATION_ID in a custom tab. This histogram is used as a means to count the total instances of custom tabs created meanwhile binning them across launching apps that have identified themselves. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. zalmashni@google.com chrome-incognito@google.com cct-team@google.com Android: This histogram is used as a means to count the total instances of Incognito custom tabs created meanwhile binning them across launching first party apps. The launching first party apps are inferred by the package name they provided when creating a custom tab connection and if we can't infer via package name then as a fallback we rely on them declaring EXTRA_APPLICATION_ID when launching Incognito custom tabs. If both fails, then the launch is recorded in the Others entry. This metric is never recorded for 3P apps. jinsukkim@chromium.org twellington@chromium.org cct-team@google.com Android: The reason a custom tab is closed. Main interest is whether a custom tab is triggered by user inputs like back press/close button click, or it is automatically closed by the app that opened it. kgrosu@google.com jinsukkim@chromium.org cct-team@google.com Android: Recorded whenever user closes the custom tab by hitting the close button or back to return to the caller app. Keeps track of the connection status and whether the app was using a KeepAlive connection. Recorded only for AGSA. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. kgrosu@google.com jinsukkim@chromium.org cct-team@google.com Android: Recorded whenever user closes the custom tab by hitting the close button or back to return to the caller app. Keeps track of the connection status and whether the app was using a KeepAlive connection. Recorded for all apps other than AGSA. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. adelm@google.com chrome-connective-tissue@google.com Records when a custom content action is displayed in the context menu in a Custom Tab, broken down by the type of content the action was for (e.g. Link or Image). This allows for tracking overall engagement with custom actions of different types with respect to the amount of times it was displayed. adelm@google.com chrome-connective-tissue@google.com Records when a custom content action is selected from the context menu in a Custom Tab, broken down by the type of content the action was for (e.g. Link or Image). This allows for tracking overall engagement with custom actions of different types. lizeb@chromium.org cct-team@google.com Time between the start of a detached resource request and its completion (failure or success). Android only. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. {DetachedResourceRequestFinalStatus} {DetachedResourceRequestSource} lizeb@chromium.org cct-team@google.com Reports the final status of the detached request, including success. Recorded once per detached resource request. Android only. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. lizeb@chromium.org cct-team@google.com Number of redirects followed by a detached resource request until success or failure. Android only. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. {DetachedResourceRequestFinalStatus} {DetachedResourceRequestSource} jinsukkim@chromium.org chrome-connective-tissue@google.com Reports some chosen specs of the device on which PCCT runs. We are interested in understanding how many devices running PCCT will be able to migrate to Activity Embedding later, which requires that the device not be a low-end one and support picture-in-picture feature. Low-endness is defined as the return value of API ActivityManager#isLowRamDevice. This is recorded only once per Chrome session, when PCCT is launched. donnd@chromium.org chrome-connective-tissue@google.com Records each feature of a Chrome Custom Tab when that feature is used. A single key feature - "Sessions" - is logged once per CCT Session, and no other feature enum may be logged more frequently. This provides a single large list of features and their percentage usage (one or more times per session) right in the UMA timeline. Recorded during a CCT Session. Android only. tivi@google.com chrome-connective-tissue@google.com Recorded only on Android. Records clicks on GoogleBottomBar buttons in the GoogleBottomBar. Logged when a button is clicked in the GoogleBottomBar (when the GoogleBottomBar feature is enabled and visible at the bottom of the CCT). tivi@google.com chrome-connective-tissue@google.com Recorded only on Android. Records GoogleBottomBar buttons that are shown. Logged when a button is displayed in the GoogleBottomBar (when the GoogleBottomBar feature is enabled and visible at the bottom of the CCT). tivi@google.com chrome-connective-tissue@google.com Recorded only on Android. Records GoogleBottomBar(GBB) buttons that are updated. Logged when embedder send request to update a button that is displayed in the GoogleBottomBar (when the GoogleBottomBar feature is enabled and visible at the bottom of the CCT). tivi@google.com chrome-connective-tissue@google.com Recorded only on Android. Records type of the layout used to create the GoogleBottomBar. Logged when the GoogleBottomBar is displayed (when the GoogleBottomBar feature is enabled and visible at the bottom of the CCT). tivi@google.com gbb-cct@google.com Whether the user supports the Google Lens entrypoint in Google Bottom Bar and if not, the reason why. Recorded when user clicks on Lens button in Google Bottom bar, that is visible only if the GoogleBottomBarVariantLayouts feature is enabled. tivi@google.com chrome-connective-tissue@google.com Recorded only on Android. Records type of the variant layout type used to create the GoogleBottomBar. Logged when the GoogleBottomBar is displayed (when the GoogleBottomBarVariant feature is enabled and visible at the bottom of the CCT). katzz@google.com chrome-connective-tissue@google.com This histogram records true when the current CCT has seen any form interactions (e.g. text entry, drop down entry) throughout the session and false if there have been no form interactions at the time of closing the CCT. If the tab is restored the previous form interactions will be reset. katzz@google.com chrome-connective-tissue@google.com This histogram records true when the current CCT has seen form interaction (e.g. text entry, drop down entry) on the active page, and false if there are no interactions in the active form, or if the interaction is reset (e.g. navigation, form submission) at the time of closing the CCT. katzz@google.com chrome-connective-tissue@google.com This histogram records true when the current CCT has interactions with the web contents (e.g. touch, scroll, fling), and the active tab can go back / forward and false if there have not been web contents interactions or the tab cannot go back / forward at the time of closing the CCT. If the tab is restored the previous form interactions will be reset. katzz@google.com chrome-connective-tissue@google.com Android only. Boolean histogram denoting whether the package name can be retrieved in a non-spoofable way for Custom Tabs. When the histogram returns true, it means we can confirm the package name was passed by the defined host app. Emitted when the Custom Tab is launched. jinsukkim@google.com chrome-connective-tissue@google.com Android only. Boolean histogram denoting whether the package name is available by the sender sharing its identity using the new API introduced in Android U. This means we can confirm the package name was passed by the defined host app. Emitted when the Custom Tab is launched. yawfrempong@google.com chrome-incognito@google.com cct-team@google.com This metrics records the caller of Incognito CCTs. For Chrome features, the feature name is recorded, for external calls, either Google App or Non-Google App categories are recorded. The metric is recorded when an Incognito CCT opening intent is received. Warning: this histogram was expired from 2026-03-23 to 2026-12-04; data may be missing. dullweber@google.com chrome-incognito@google.com cct-team@google.com This metrics records whether a caller who requested Incognito CCT is considered trusted. Only recorded when CCTIncognitoAvailableToThirdParty is false. lizeb@chromium.org Android only. Which flavors of mayLaunchUrl() were used before a tab launch. Can be low and/or high confidence. Recorded at the same time as CustomTabs.WarmupStateOnLaunch for the buckets "Session, No Warmup, Warmup called from another UID", "Session, No Warmup" and "Session, Warmup". Before M118, unlike CustomTabs.WarmupStateOnLaunch, this metric was only recorded with a valid session. sinansahin@google.com chrome-connective-tissue@google.com Emitted when the the user clicks the minimize button and we request to be put in picture-in-picture from the framework. Records true if it was successful; false if there was an exception thrown. Android only. sinansahin@google.com chrome-connective-tissue@google.com Minimized Custom Tab feature availability. Recorded during startup in #onFinishNativeInitialization() when the availability is first checked to initialize the feature. Android only. adelm@google.com chrome-connective-tissue@google.com The reason the custom tab activity was finished. Recorded during the #finish() phase under CustomTabActivityNavigationController. jinsukkim@chromium.org clank-app-team@chromium.org Records the navigation event occurring in CustomTab and being reported to the host app via CustomTabsCallback. Recorded when the events are notified to the host app. Android only. ender@google.com sinansahin@google.com Records whether a CustomTab was requested to include an interactive Omnibox. Recorded once per CCT instantiation event. Android only. ender@google.com sinansahin@google.com Records whether user initiated navigation after focusing the Omnibox. Value of 'true' indicates user chose to initiate navigation, whereas value of 'false' suggests the user abandoned the interaction with the Omnibox. Recorded once per interaction with Omnibox on CCT when the CCT receives a response from SearchActivity. Android only. ender@google.com sinansahin@google.com Records the number of navigations issued on CustomTab during its lifetime. Recorded only on CCTs that feature an interactive Omnibox. Recorded once per CCT when CCT is about to be destroyed. Android only. jinsukkim@chromium.org chrome-connective-tissue@google.com Records how CCT was opened i.e. opened as a new one, opened on top of Google search widget results via CCT omnibox, or restored from a disk state file. Recored once per CCT when it is initialized. Android only. jinsukkim@google.com tivi@google.com chrome-connective-tissue@google.com Records Custom Tab page content features eligibility, detailing if it was enabled by embedder, by Chrome developer experiment, or disqualified. Android only. Logged once per button click. jinsukkim@google.com tivi@google.com chrome-connective-tissue@google.com Records the detailed outcome of requesting/generating page content values (annotated page content URI, screenshots, or file content URIs) for Custom Tabs actions. Android only. Logged once per button click. jinsukkim@google.com tivi@google.com chrome-connective-tissue@google.com Records each content type (APC, Screenshot, or File) requested inside the custom bottom bar view click map from Embedder. Android only. Logged once per button click. jinsukkim@chromium.org chrome-connective-tissue@google.com Recorded only on Android. Holds the interaction that the user has with Page Insights BottomSheet, such as invoking PIH manually or by being auto triggered, the bottom sheet's states and when it is dismissed, and interactions with xSurface views. jinsukkim@chromium.org chrome-connective-tissue@google.com Network error code occuring upon page navigation. Recorded each time Custom tabs receives an event TabObserver.onPageLoadFailed. lizeb@chromium.org cct-team@google.com mthiesse@chromium.org Recorded only on Android. Whether a parallel request was requested by the calling application, and if so its initial status. Recorded once per handled intent, when the request is initiated. Filter the platform for just CCT/TWA data. Expired in M120 and brought back in M144. kgrosu@google.com chrome-connective-tissue@google.com Type of the Partial Custom Tab that has been created. A new entry will be logged each time a PCCT is opened or when the user transitions from a type of PCCT to another (e.g. on screen rotation if the type changes from bottom-sheet to side-sheet). Multiple entries can be logged for each PCCT that is being displayed. elabadysayed@chromium.org chrome-connective-tissue@google.com Android only. Recorded when the CCT client calls requestPostMessageChannel to establish a two way postMessage channel. Emits true if the request is with targetOrigin specified and false otherwise. That should determine if we can to delete the old API (Without targetOrigin) or not. taiyo@chromium.org chrome-prerendering@google.com UseCounter for Custom Tabs Prefetch API. True should be recorded when CustomTabsConnection.prefetch is called. False should never be recorded. Android CCT only. tivi@google.com chrome-connective-tissue@google.com Records the elapsed time in minutes from when the user leaves a Custom Tab until they return. This is recorded for sessions with an active timeout. The value is capped at 3 hours. Recorded upon returning to a CCT. Recorded multiple times throughout the CCT session, but only once per "leave cycle". (A leave cycle is the period of time starting when the user navigates away from the Custom Tab tracked by activity.onStop until they return tracked by activity.onResume or the CCT is closed tracked by activity.onDestroy.) tivi@google.com chrome-connective-tissue@google.com Records whether the Custom Tab timeout was configured by the embedding app (true) or by a Chrome experiment (false). Recorded when a CCT session is started. Recorded once per CCT session. tivi@google.com chrome-connective-tissue@google.com Records the outcome of Custom Tab sessions that have a configured timeout. This metric captures whether the timeout was triggered and how the session was handled (e.g., closed due to timeout, timeout ignored). Recorded when a CCT session with an active timeout concludes or the timeout condition is evaluated. Recorded multiple times throughout the CCT session, but only once per "leave cycle"(A leave cycle is the period of time starting when the user navigates away from the Custom Tab tracked by activity.onStop until they return tracked by activity.onResume or the CCT is closed tracked by activity.onDestroy.) wenyufu@chromium.org chrome-connective-tissue@google.com When a CCT session is launched, if it is launched with same URL and has the same package name or the same taskId + referrer combo, record the duration between previous CCT closure and current CCT launch. Recorded on CCT launch. A CCT can be defined as retainable if 1) it is launching with the same URL as the most recently closed CCT; 2) it is launched from the same embedded app as the most recently closed CCT; 3) the most recently closed CCT had user interactions. See "CustomTabs.HadInteractionOnClose.Form" and "CustomTabs.HadInteractionOnClose.Navigation" for information on interactions. The histogram suffix identifies whether the CCT is created with the same intent Uri data and for the same embedded app, launching CCT with the same taskId and package name. The package name identifier to use will depend on whether the client app is using CustomTabService. If app is using the CCT service, the package name will be read from CCT service; otherwise the package name is read from the referrer of CCT activity. This histogram is recorded for {IdentifierType} kgrosu@google.com chrome-connective-tissue@google.com Recorded only for Android. Record information about the state of the client app, custom tab and system in the moment the connection between the client and the custom tab is terminated. With this, we are trying to understand how often a connection is terminated (the client app dies/is killed/is closed) while a custom tab is in foreground. Also, if the EXTRA_KEEP_ALIVE is set, we want to understand if it reduces the number of connections being terminated. The aim is that CT_FOREGROUND and CT_FOREGROUND_KEEPALIVE are logged as little as possible, while the rest of the states are expected ways in which a connection may be terminated. *CT_FOREGROUND*/*CT_BACKGROUND* - an enum value that contains this text reflects if the custom tab was in the foreground/background when the connection was terminated. *KEEP_ALIVE* - an enum value that contains this text reflects that the EXTRA_KEEP_ALIVE intent extra was specified and that the custom tab binds to the service provided by it in order to increase the priority of the client app to foreground. *LOW_MEMORY* - an enum value that contains this text reflects that the system was low on memory when the connection was terminated. This does not mean that this was indeed the reason for the connection being terminated, but it might be a good indicator of it. UNKNOWN - if this is logged then there is probably a bug in the code as we have a state we can be in that we don't currently account for. adelm@google.com chrome-connective-tissue@google.com Android: Record whether a spare renderer was created when closing a custom tab. There are two possible scenarios here: (1) The web page is opened in the same browser by reparenting the tab into the browser and no spare renderer is created. (2) Any other finish reason should result in the creation of a spare renderer. This metric will help us determine whether enabling predictive back gesture and deferring to the OS and letting it handle the clean up process impacts the spare renderer creation process. This will determine whether the behavior remains the same for the enabled and control groups to ensure that the feature or change being tested in the 'enabled' group does not introduce unintended behavioral regressions or deviations from the baseline. mthiesse@chromium.org chrome-connective-tissue@google.com Whether or not Navigation was started early for Custom Tab startup. Excludes WebApp/WebApk startups. mthiesse@chromium.org chrome-connective-tissue@google.com Startup time for a Custom Tab from the earliest point in startup to the first navigation commit. Split by varying degrees of warmness, from cold to fully pre-loaded through mayLaunchUrl. It is recommended to limit analysis of data to Android P+ because on prior versions the cold start detection is less robust. NOTE: This metric is broken before October 2024 on Pixel 6+ on Android 14+ due to an issue with the recording of BrowserProcessCreationReason affecting ColdStartTracker downstream. {suffix}. mthiesse@chromium.org chrome-connective-tissue@google.com Startup time for a Custom Tab from the earliest point in startup to the First Contentful Paint on the first navigation. Split by varying degrees of warmness, from cold to fully pre-loaded through mayLaunchUrl. It is recommended to limit analysis of data to Android P+ because on prior versions the cold start detection is less robust. NOTE: This metric is broken before October 2024 on Pixel 6+ on Android 14+ due to an issue with the recording of BrowserProcessCreationReason affecting ColdStartTracker downstream. {suffix}. mthiesse@chromium.org chrome-connective-tissue@google.com Startup time for a Custom Tab from the earliest point in startup to the Largest Contentful Paint on the first navigation. Split by varying degrees of warmness, from cold to fully pre-loaded through mayLaunchUrl. It is recommended to limit analysis of data to Android P+ because on prior versions the cold start detection is less robust. NOTE: This metric is broken before October 2024 on Pixel 6+ on Android 14+ due to an issue with the recording of BrowserProcessCreationReason affecting ColdStartTracker downstream. {suffix}. nafisabedin@google.com The time spent in milliseconds processing IPCs on the UI thread related to Realtime Engagement events for CCTs. Recorded only for Android, once per CCT session after the #onSessionEnded call, if Realtime Engagement signals are enabled. yusufo@chromium.org src/base/metrics/OWNERS Recorded only for Android. Records on every metrics upload whether the currently visible tab is a custom tab. The custom tab is launched by a client app with customized UI. Some metrics like page load time will behave differently for these tabs since it will be possible to warm up the browser process and prepare resources for specific urls ahead of time via a service connection. This histogram can be used to cluster these metric differently. As of M87, this histogram is logged on a log start, rather than log end to tag more logs. lizeb@chromium.org Recorded only on Android. Reports whether warmup() has been called when a Custom Tabs Intent is received from an application, and if so, whether the call could be matched with a session. Starting with M84 this is is also recorded for webapps/WebAPKs. Filter the platform for just CCT/TWA data. vkorotkevich@google.com pwa-team@google.com Records the usage of back button when running a web app. This is recorded only for minimal ui display mode in Trusted Web Activities and WebAPKs. vkorotkevich@google.com pwa-team@google.com Records how long PWA controls are hidden due to the window size being too small. Recorded when transitioning hidden to shown, and on destruction. The second version is intorduced, because previously milliseconds were recorded. vkorotkevich@google.com pwa-team@google.com Records how long PWA controls are shown before being hidden due to window size changes. Recorded when transitioning shown to hidden, and on destruction. The second version is intorduced, because previously milliseconds were recorded. vkorotkevich@google.com pwa-team@google.com Records the DisplayMode of the the PWA header when it first becomes visible. This histogram is a fixed version of a previous one, because buckets didn't match DisplayMode enum values. vkorotkevich@google.com pwa-team@google.com Records the usage of reload button when running a web app. This is recorded only for minimal ui display mode in Trusted Web Activities and WebAPKs. lizeb@chromium.org mthiesse@chromium.org Android: When a CustomTabActivity creates its Tab, whether we use a prerendered WebContents, a spare renderer or create a new WebContents. Note: Expired from April 13-25, 2025. peconn@chromium.org src/chrome/android/java/src/org/chromium/chrome/browser/browserservices/OWNERS Records whether the extra command {command} called from TrustedWebActivityClient resulted in success or failure. tkachenkoo@google.com sselyvon@google.com lt-web-apps-team@google.com Warning: this histogram was expired from 2026-05-01 to 2026-07; data may be missing. Records the client mode of a web app launched through Trusted Web Activity. Client mode is a part of Launch Handler API. Recorded on Trusted Web Activity startup if the Launch Handler API is enabled. tkachenkoo@google.com sselyvon@google.com lt-web-apps-team@google.com Warning: this histogram was expired from 2026-05-01 to 2026-07; data may be missing. Records the verification failure that caused launch queue to not be notified in Trusted Web Activity, if any. Recorded on Trusted Web Activity startup if the Launch Handler API is enabled. tkachenkoo@google.com sselyvon@google.com lt-web-apps-team@google.com Warning: this histogram was expired from 2026-05-01 to 2026-07; data may be missing. Records the usage of file handling API in Trusted Web Activities, as part of Launch Handler API. Recorded on Trusted Web Activity startup if the Launch Handler API is enabled. If file handling is not used, NO_FILES will be reported. peconn@chromium.org src/chrome/android/java/src/org/chromium/chrome/browser/browserservices/OWNERS Warning: this histogram was expired from 2026-02-01 to 2026-07; data may be missing. The result of a TWA notification permission request for the purpose of notification delegation. This is logged when the NotificationPermissionUpdater receives the result from the TrustedWebActivityClient. hattorij@google.com ishitatsuyuki@google.com lt-performance@google.com Duration for a TWA from the launch of the TWA to the first navigation commit. Split by varying degrees of warmness, from cold to fully pre-loaded through mayLaunchUrl. {suffix}. hattorij@google.com ishitatsuyuki@google.com lt-performance@google.com Duration for a TWA from the launch to the First Contentful Paint on the first navigation. Split by varying degrees of warmness, from cold to fully pre-loaded through mayLaunchUrl. {suffix}. hattorij@google.com ishitatsuyuki@google.com lt-performance@google.com Duration for a TWA from the launch to the Largest Contentful Paint on the first navigation. Split by varying degrees of warmness, from cold to fully pre-loaded through mayLaunchUrl. {suffix}.