tools/metrics/histograms/metadata/sync/histograms.xml

<!--
Copyright 2020 The Chromium Authors
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 Sync 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 follow the instructions in the OWNERS file in this directory to find a
reviewer. If no OWNERS file exists, please consider signing up at
go/reviewing-metrics (Googlers only), as all subdirectories are expected to
have an OWNERS file. As a last resort you can send the CL to
chromium-metrics-reviews@google.com.
-->

<histogram-configuration>

<histograms>

<variants name="SyncModelType">
  <variant name=".APP" summary="APP"/>
  <variant name=".APP_LIST" summary="APP_LIST"/>
  <variant name=".APP_SETTING" summary="APP_SETTING"/>
  <variant name=".ARC_PACKAGE" summary="ARC_PACKAGE"/>
  <variant name=".AUTOFILL" summary="AUTOFILL"/>
  <variant name=".AUTOFILL_OFFER" summary="AUTOFILL_OFFER"/>
  <variant name=".AUTOFILL_PROFILE" summary="AUTOFILL_PROFILE"/>
  <variant name=".AUTOFILL_WALLET" summary="AUTOFILL_WALLET"/>
  <variant name=".AUTOFILL_WALLET_USAGE" summary="AUTOFILL_WALLET_USAGE"/>
  <variant name=".BOOKMARK" summary="BOOKMARK"/>
  <variant name=".CONTACT_INFO" summary="CONTACT_INFO"/>
  <variant name=".DEVICE_INFO" summary="DEVICE_INFO"/>
  <variant name=".DICTIONARY" summary="DICTIONARY"/>
  <variant name=".EXTENSION" summary="EXTENSION"/>
  <variant name=".EXTENSION_SETTING" summary="EXTENSION_SETTING"/>
  <variant name=".HISTORY" summary="HISTORY"/>
  <variant name=".HISTORY_DELETE_DIRECTIVE" summary="HISTORY_DELETE_DIRECTIVE"/>
  <variant name=".MANAGED_USER_SETTING" summary="MANAGED_USER_SETTING"/>
  <variant name=".NIGORI" summary="NIGORI"/>
  <variant name=".OS_PREFERENCE" summary="OS_PREFERENCE"/>
  <variant name=".OS_PRIORITY_PREFERENCE" summary="OS_PRIORITY_PREFERENCE"/>
  <variant name=".PASSWORD" summary="PASSWORD"/>
  <variant name=".POWER_BOOKMARK" summary="POWER_BOOKMARK"/>
  <variant name=".PREFERENCE" summary="PREFERENCE"/>
  <variant name=".PRINTERS" summary="PRINTERS"/>
  <variant name=".PRINTERS_AUTHORIZATION_SERVERS"
      summary="PRINTERS_AUTHORIZATION_SERVERS"/>
  <variant name=".PRIORITY_PREFERENCE" summary="PRIORITY_PREFERENCE"/>
  <variant name=".PROXY_TABS" summary="PROXY_TABS"/>
  <variant name=".READING_LIST" summary="READING_LIST"/>
  <variant name=".SAVED_TAB_GROUPS" summary="SAVED_TAB_GROUPS"/>
  <variant name=".SEARCH_ENGINE" summary="SEARCH_ENGINE"/>
  <variant name=".SECURITY_EVENT" summary="SECURITY_EVENT"/>
  <variant name=".SEGMENTATION" summary="SEGMENTATION"/>
  <variant name=".SEND_TAB_TO_SELF" summary="SEND_TAB_TO_SELF"/>
  <variant name=".SESSION" summary="SESSION"/>
  <variant name=".SHARING_MESSAGE" summary="SHARING_MESSAGE"/>
  <variant name=".THEME" summary="THEME"/>
  <variant name=".TYPED_URL" summary="TYPED_URL"/>
  <variant name=".USER_CONSENT" summary="USER_CONSENT"/>
  <variant name=".USER_EVENT" summary="USER_EVENT"/>
  <variant name=".WALLET_METADATA" summary="WALLET_METADATA"/>
  <variant name=".WEB_APP" summary="WEB_APP"/>
  <variant name=".WIFI_CONFIGURATION" summary="WIFI_CONFIGURATION"/>
  <variant name=".WORKSPACE_DESK" summary="WORKSPACE_DESK"/>
</variants>

<variants name="TrustedVaultTimeSinceMigrationSuffix">
  <variant name=""
      summary="Includes data for users that went through migration any time
               (including unknown and invalid)."/>
  <variant name=".MigratedLast3Days"
      summary="Includes data for users that went through migration during the
               last 3 days (wrt recording the metrics)."/>
  <variant name=".MigratedLast7Days"
      summary="Includes data for users that went through migration during the
               last 7 days (wrt recording the metrics)."/>
  <variant name=".MigratedLast28Days"
      summary="Includes data for users that went through migration during the
               last 28 days (wrt recording the metrics)."/>
  <variant name=".MigratedLastDay"
      summary="Includes data for users that went through migration during the
               last day (wrt recording the metrics)."/>
</variants>

<histogram name="FCMInvalidations.SubscriptionResponseCodeForTopic{Topic}"
    enum="HttpResponseCode" expires_after="never">
<!-- TODO(crbug.com/1266807): Move back to */invalidation/histograms.xml once
    variants can be shared across files. -->

  <owner>melandory@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <summary>
    For each subcription request to the FCM Per-User-Topic server, log the
    response received from the server per topic. Note: This is only recorded
    with a data type suffix. The base version is never recorded.
  </summary>
  <token key="Topic" variants="SyncModelType">
    <variant name=".OTHER" summary="OTHER"/>
  </token>
</histogram>

<histogram name="Sync.BackedOffModelType" enum="SyncModelTypes"
    expires_after="2023-06-25">
  <owner>victorvianna@google.com</owner>
  <owner>src/components/sync/OWNERS</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Logged when a data type is backed off.

    This histogram can help explain changes in
    Sync.PostedClientToServerMessageError2::PARTIAL_FAILURE.
  </summary>
</histogram>

<histogram name="Sync.BookmarkEntityReuploadNeeded.On{UpdateType}"
    enum="Boolean" expires_after="2023-10-30">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records if the entity is marked to be reuploaded. It is recorded on each
    incoming bookmark update from the server during {UpdateType}.
  </summary>
  <token key="UpdateType">
    <variant name="IncrementalUpdate" summary="incremental update"/>
    <variant name="InitialMerge" summary="initial merge"/>
  </token>
</histogram>

<histogram name="Sync.BookmarkGUIDSource2" enum="BookmarkGUIDSource"
    expires_after="2023-06-18">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether a GUID was found within BookmarkSpecifics, if an
    originator_client_item_id of valid GUID format was used to replace it, or if
    the field was left empty. Recorded when processing a remote bookmark update,
    except for permanent nodes, which are created server-side and don't have an
    originator client item ID.
  </summary>
</histogram>

<histogram name="Sync.BookmarkModelMerger.ReachableInputUpdates"
    units="bookmarks" expires_after="2023-03-19">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the number of valid and non-duplicate updates processed during
    initial merge for bookmarks that are reachable when traversing the bookmark
    tree, including permanent folders. Recorded during the initial merge
    procedure after deduplication.
  </summary>
</histogram>

<histogram name="Sync.BookmarkModelMerger.UnsyncedEntitiesUponCompletion"
    units="bookmarks" expires_after="2023-03-19">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the number of unsynced entities (bookmarks or folders) as a result
    of the initial merge for bookmarks. This includes local creations (i.e. did
    not match any entity in the server) as well as local modifications (e.g.
    pending reupload). Recorded upon completion of the initial merge procedure.
  </summary>
</histogram>

<histogram name="Sync.BookmarkModelMerger.ValidInputUpdates" units="bookmarks"
    expires_after="2023-06-25">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the number of received input updates considered valid during initial
    merge for bookmarks, prior to deduplication, including permanent folders and
    unreachable nodes (see Sync.BookmarkModelMerger.ReachableInputUpdates for a
    more strict variant). Invalid updates contribute to metric
    Sync.ProblematicServerSideBookmarksDuringMerge. Recorded during the initial
    merge procedure.
  </summary>
</histogram>

<histogram name="Sync.BookmarkModelMergerTime{UpdatesCount}" units="ms"
    expires_after="2023-08-01">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Measures the initial bookmark merge time broken down by different stages.
    Recorded after every initial merge procedure {UpdatesCount}.
  </summary>
  <token key="UpdatesCount">
    <variant name="" summary="regardless of the number of updates"/>
    <variant name=".10kUpdates" summary="having more than 10k remote updates"/>
    <variant name=".50kUpdates" summary="having more than 50k remote updates"/>
    <variant name=".100kUpdates"
        summary="having more than 100k remote updates"/>
  </token>
</histogram>

<histogram name="Sync.BookmarksGUIDDuplicates" enum="BookmarksGUIDDuplicates"
    expires_after="2023-07-16">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records different types of bookmark entities having the same GUIDs. It's
    recorded on each found duplicate when processing remote bookmarks from the
    sync server during the initial merge.
  </summary>
</histogram>

<histogram name="Sync.BookmarksModelMetadataCorruptionReason"
    enum="SyncBookmarkModelMetadataCorruptionReason" expires_after="2023-07-09">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    The reason why the persisted metadata for a bookmark model is considered
    corrupted. It either has corrupted data or doesn't match the bookmark model.
    It's recorded at start up only if the initial sync has been performed
    already. It's recorded after loading the metadata.
  </summary>
</histogram>

<histogram name="Sync.BookmarkSpecificsExcludingFoldersContainFavicon"
    enum="Boolean" expires_after="2023-03-19">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records if a remote sync update for a bookmark, excluding folders, contains
    a favicon. It is recorded upon initial and incremental updates, when the
    local state is about to be modified.
  </summary>
</histogram>

<histogram name="Sync.CommitResponseForUnknownEntity" enum="SyncModelTypes"
    expires_after="2023-06-30">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Emitted when a Commit entity response is received for an unknown entity
    (i.e. for a client tag hash that doesn't correspond to a tracked entity).
  </summary>
</histogram>

<histogram name="Sync.CommitResponse{SyncModelType}" enum="SyncerErrorValues"
    expires_after="2023-04-10">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Emitted per network Commit() request to the sync server and datatype.
    Records the outcome of each commit attempt per data type (success or one of
    various error codes).
  </summary>
  <token key="SyncModelType" variants="SyncModelType">
    <variant name="" summary="Any type"/>
  </token>
</histogram>

<histogram name="Sync.ConfigureDataTypeManagerOption"
    enum="SyncFeatureOrTransport" expires_after="2023-06-04">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Whether the full Sync feature or only the Sync transport layer is being
    configured. Recorded when configuring the data types for any reason: Most
    commonly during browser startup, but also after initial setup, after a
    reconfiguration by the user, or when switching between full feature mode and
    transport mode.
  </summary>
</histogram>

<histogram name="Sync.ConfigureDataTypes" enum="SyncModelTypes"
    expires_after="2023-07-09">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Breakdown of sync data types being configured at first time signin, restart,
    or user-initiated reconfiguration. This is different from Sync.CustomTypes
    in that this captures all active devices, not just those that are choosing a
    custom sync configuration.

    Note that not all platforms support all data types. As such, comparing
    across platforms should only look at the common data types.
  </summary>
</histogram>

<histogram name="Sync.ConfigureTime_{ConfigurationType}.{Result}" units="ms"
    expires_after="2023-08-09">
  <owner>victorvianna@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Time spent configuring data types for {ConfigurationType}. Recorded when
    DataTypeManagerImpl finishes.
  </summary>
  <token key="ConfigurationType">
    <variant name="Initial" summary="initial sync"/>
    <variant name="Subsequent" summary="subsequent (non-first) sync"/>
  </token>
  <token key="Result">
    <variant name="ABORTED" summary="When configuration gets aborted."/>
    <variant name="OK" summary="When configuration is successful"/>
  </token>
</histogram>

<histogram
    name="Sync.Crypto.CustomPassphraseKeyDerivationMethodOnSuccessfulDecryption"
    enum="SyncCustomPassphraseKeyDerivationMethodState"
    expires_after="2023-07-09">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Key derivation method used for sync custom passphrase on successful
    decryption of pending keys, i.e. when a passphrase is requested and the user
    types in the correct one. &quot;Not set&quot; will never be reported for
    this metric, since we always have an explicit key derivation method on
    successful decryption.
  </summary>
</histogram>

<histogram name="Sync.Crypto.CustomPassphraseKeyDerivationMethodStateOnStartup"
    enum="SyncCustomPassphraseKeyDerivationMethodState"
    expires_after="2023-07-09">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    State of the derivation method used for sync custom passphrase on startup.
    Reported only when the passphrase type is CUSTOM_PASSPHRASE.
  </summary>
</histogram>

<histogram name="Sync.Crypto.NigoriKeyDerivationDuration.{Method}" units="ms"
    expires_after="2023-05-01">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Time taken to derive keys in Nigori using a given key derivation method.
    This histogram is always recorded with one of the key derivation method
    suffixes.
  </summary>
  <token key="Method">
    <variant name="Pbkdf2" summary="PBKDF2_HMAC_SHA1_1003"/>
    <variant name="Scrypt8192" summary="SCRYPT_8192_8_11"/>
  </token>
</histogram>

<histogram name="Sync.CryptographerPendingKeys"
    enum="SyncCryptographerPendingKeysState" expires_after="2023-06-04">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Breakdown of sync users whose cryptographer has pending keys.
  </summary>
</histogram>

<histogram name="Sync.CryptographerReady" enum="SyncCryptographerReadyState"
    expires_after="2023-07-09">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Breakdown of sync users whose cryptographer is fully ready for encryption
    and decryption (initialized and no pending keys).
  </summary>
</histogram>

<histogram name="Sync.CustomEncryption" enum="SyncCustomEncryptionEvent"
    expires_after="2023-06-04">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Histogram that keeps track of how users encrypt their sync data. All users
    start off with default encryption during initial setup, while a subset of
    users go on to encrypt their sync data with a custom passphrase.
  </summary>
</histogram>

<histogram name="Sync.CustomOSSync" enum="SyncModelTypes"
    expires_after="2023-05-14">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    For users who have *not* selected the &quot;Sync Everything&quot; option,
    this records all the OS data types they have selected to sync. Samples are
    taken every time the Sync data types are (re)configured, which typically
    happens during startup and when the user changes any Sync settings.
  </summary>
</histogram>

<histogram name="Sync.CustomSync3" enum="SyncModelTypes"
    expires_after="2023-06-25">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    For users who have *not* selected the &quot;Sync Everything&quot; option,
    this records all the data types they have selected to sync. Samples are
    taken every time the Sync data types are (re)configured, which typically
    happens during startup and when the user changes any Sync settings.

    NOTE: this does NOT include OS datatypes. Use Sync.CustomOSSync for those.
  </summary>
</histogram>

<histogram name="Sync.DataTypeRunFailures2" enum="SyncModelTypes"
    expires_after="2023-07-09">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Histogram of the run failures for the different sync datatypes. These are
    failures that occur after startup while the datatype is syncing. This is one
    of the base sync health metrics. The Sync.ModelTypeStoreBackendError
    histograms may help diagnosing the problem.
  </summary>
</histogram>

<histogram name="Sync.DataTypeStartFailures2" enum="SyncModelTypes"
    expires_after="2023-07-09">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Histogram of the startup failures for the different sync datatypes. These
    are failures that occur during startup before the data type is fully loaded.
    These errors are caused by failures in reading metadata (or data) from the
    DB or by another failure in interaction with the model. The
    Sync.ModelTypeStoreBackendError histograms may help diagnosing the problem.
  </summary>
</histogram>

<histogram name="Sync.DeviceCount2" units="devices" expires_after="never">
<!-- expires-never: used internally for filtering -->

  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <owner>chrome-metrics-team@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    The largest number of active and concurrently syncing devices known to any
    profile. May be 0 when there are no signed in/syncing profiles open. Logged
    with every UMA log.
  </summary>
</histogram>

<histogram name="Sync.DeviceCount2.{DeviceType}" units="devices"
    expires_after="2023-11-02">
  <owner>ssid@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <owner>chrome-metrics-team@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    The largest number of active and concurrently syncing devices of type
    {DeviceType} known to any profile. May be 0 when there are no signed
    in/syncing profiles open. Logged with every UMA log.
  </summary>
  <token key="DeviceType">
    <variant name="Desktop"/>
    <variant name="Phone"/>
    <variant name="Tablet"/>
  </token>
</histogram>

<histogram name="Sync.EntitySizeOnCommit.{SyncModelType}" units="bytes"
    expires_after="2023-11-30">
  <owner>ankushkush@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Size of individual sync entities in bytes. Recorded right before an entity
    is committed to the server.
  </summary>
  <token key="SyncModelType" variants="SyncModelType"/>
</histogram>

<histogram name="Sync.FCMInstanceIdTokenRetrievalStatus"
    enum="InstanceIDResult" expires_after="2023-06-18">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records status of each attempt to retrieve the instance id token. Replaces
    FCMInvalidations.InitialTokenRetrievalStatus for Sync standalone
    invalidations.
  </summary>
</histogram>

<histogram name="Sync.FCMMessageDeliveredToListeners" enum="Boolean"
    expires_after="2023-04-16">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Whether an incoming FCM message has been delivered to at least one listener.
    Recorded on each incoming FCM message for standalone Sync invalidations.
  </summary>
</histogram>

<histogram name="Sync.History.DatabaseError" enum="SyncHistoryDatabaseError"
    expires_after="2023-06-30">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded when HistorySyncBridge encounters a database error. As a result,
    the bridge stops operating (and tracking metadata) for the rest of the
    runtime of Chrome.
  </summary>
</histogram>

<histogram name="Sync.History.IncomingSpecificsError"
    enum="SyncHistorySpecificsError" expires_after="2023-06-30">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded when HistorySyncBridge encounters an incoming entity that is
    invalid, i.e. that fails some validity check. Counts in this histogram
    should be compared to counts in the &quot;Remote&quot; buckets of
    Sync.ModelTypeEntityChange3.History.
  </summary>
</histogram>

<histogram name="Sync.IncomingInvalidationStatus"
    enum="SyncIncomingInvalidationStatus" expires_after="2023-05-27">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    An outcome of handling incoming sync invalidations, recorded for each
    incoming FCM message when sync engine is registered for invalidations. This
    metric shows only the number of incoming messages regardless of the number
    of invalidated data types.
  </summary>
</histogram>

<histogram name="Sync.InitialState" enum="SyncInitialState"
    expires_after="M110">
  <obsolete>
    Replaced in M108 by Sync.InitialState2.
  </obsolete>
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    NOTE: This histogram is also recorded (with value &quot;No signed in
    user&quot;) for profiles in which Sync will never be able to start, such as
    the system profile (used for the profile picker). You probably want to look
    at Sync.InitialState2 instead.

    An approximate state of sync at profile startup. Logs a few reasons sync
    definitely wouldn't be able to start, or that it probably can start. A
    dashboard stop and clear will fall under &quot;turned off and setup not
    completed&quot;.
  </summary>
</histogram>

<histogram name="Sync.InitialState2" enum="SyncInitialState"
    expires_after="2023-07-09">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    An approximate state of sync at profile startup. Logs a few reasons sync
    definitely wouldn't be able to start, or that it probably can start. A
    dashboard stop and clear will fall under &quot;turned off and setup not
    completed&quot;. Only recorded for &quot;regular&quot; profiles, i.e. those
    in which Sync might actually start. This excludes incognito profiles, guest
    profiles, system profiles (used for the profile picker), lockscreen
    profiles, etc.
  </summary>
</histogram>

<histogram name="Sync.InvalidationPerModelType" enum="SyncModelTypes"
    expires_after="never">
<!-- expires-never: For monitoring FCM based invalidations. -->

  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Histogram tracks the number of invalidations received per sync data type.
  </summary>
</histogram>

<histogram name="Sync.InvalidBookmarkSpecifics"
    enum="InvalidBookmarkSpecificsError" expires_after="2023-04-23">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records different causes for BookmarkSpecifics to be deemed invalid. Issues
    are recorded upon verifying validity of specifics received from the server.
  </summary>
</histogram>

<histogram name="Sync.KeystoreDecryptionFailed"
    enum="SyncKeystoreDecryptionFailure" expires_after="2023-05-06">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>The reason for a failure decrypting the keystore Nigori.</summary>
</histogram>

<histogram name="Sync.Local.Enabled" enum="BooleanEnabled" expires_after="M110">
  <obsolete>
    Replaced in M108 by Sync.Local.Enabled2.
  </obsolete>
  <owner>igorruvinov@chromium.org</owner>
  <owner>pastarmovj@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    NOTE: This histogram is also recorded for profiles in which Sync will never
    be able to start, such as the system profile (used for the profile picker).
    You probably want to look at Sync.Local.Enabled2 instead.

    Tracks the number of times the local sync backend was enabled by the user.
    Recorded when the SyncService is created, i.e. during profile startup.
  </summary>
</histogram>

<histogram name="Sync.Local.Enabled2" enum="BooleanEnabled"
    expires_after="2023-06-11">
  <owner>igorruvinov@chromium.org</owner>
  <owner>pastarmovj@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Tracks the number of times the local sync backend was enabled by the user.
    Recorded when the SyncService is created, i.e. during profile startup.
  </summary>
</histogram>

<histogram name="Sync.Local.FileSizeKB" units="KB" expires_after="2023-05-27">
  <owner>igorruvinov@chromium.org</owner>
  <owner>pastarmovj@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Tracks the size of the local sync backend database file. Recorded every time
    the roaming profile file is written by the client.
  </summary>
</histogram>

<histogram name="Sync.Local.ReadPlatformFileError" enum="PlatformFileError"
    expires_after="2023-06-04">
  <owner>igorruvinov@chromium.org</owner>
  <owner>pastarmovj@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Error code describing failure to read persisted sync state from local file.
    Recorded when an error is encountered during opening or reading of the local
    sync state file.
  </summary>
</histogram>

<histogram name="Sync.Local.RoamingProfileUnavailable" enum="BooleanError"
    expires_after="M110">
  <obsolete>
    Replaced in M108 by Sync.Local.RoamingProfileUnavailable2.
  </obsolete>
  <owner>igorruvinov@chromium.org</owner>
  <owner>pastarmovj@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    NOTE: This histogram is also recorded for profiles in which Sync will never
    be able to start, such as the system profile (used for the profile picker).
    You probably want to look at Sync.Local.RoamingProfileUnavailable2 instead.

    Tracks the number of times the Roaming profile cannot be retrieved. Recorded
    when the SyncService is created, i.e. during profile startup.
  </summary>
</histogram>

<histogram name="Sync.Local.RoamingProfileUnavailable2" enum="BooleanError"
    expires_after="2023-08-01">
  <owner>igorruvinov@chromium.org</owner>
  <owner>pastarmovj@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Tracks the number of times the Roaming profile cannot be retrieved. Recorded
    when the SyncService is created, i.e. during profile startup.
  </summary>
</histogram>

<histogram name="Sync.LocalDeviceInfoDeletionReuploaded" enum="Boolean"
    expires_after="2023-06-30">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded after receiving an incoming deletion of local DeviceInfo during
    incremental update. Counts whether the local DeviceInfo is marked to be
    reuploaded.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeBlockedDueToUndecryptableUpdate"
    enum="SyncModelTypes" expires_after="2023-03-26">
  <owner>victorvianna@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded on every GetUpdatesResponse if the data type is blocked because due
    to the existence of undecryptable updates sent by the server. This is *not*
    recorded for the cases where sync encryption is in a valid pending state,
    e.g. user hasn't entered their passphrase yet.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeCommitMessageHasDepletedQuota"
    enum="SyncModelTypes" expires_after="2023-06-25">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded once per commit message after which the quota for the given data
    type is depleted. If the commit cycle contains 150 commit messages for a
    given data type and the quota has initially 100 tokens, the quota gets
    depleted after first 100 messages and this histogram gets recorded for all
    the remaining messages (i.e. ~50 times) for the data type. Quota is tracked
    (and this metric gets recorded) only for data types that can be committed
    via JS API of extensions.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeCommitWithDepletedQuota" enum="SyncModelTypes"
    expires_after="2023-04-04">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded once per local change that gets scheduled for committing with an
    extra long nudge delay. This happens if and only if the commit quota for
    this data type for this user is depleted. Quota is tracked (and this metric
    gets recorded) only for data types that can be committed via JS API of
    extensions. This metric is not very reliable as nudging for local changes
    happens via thread hopping and there is no guarantee whether a local change
    will nudge for commit _before_ or _after_ it actually gets committed.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeConfigurationTime.{StorageType}{SyncModelType}"
    units="ms" expires_after="2023-03-06">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded once per activation of a(n) {StorageType} data type; the value is
    the duration of the setup (time from the start of the configuration of sync
    until the data type receives all its sync data and the data is ready for the
    user). This metric is used for monitoring general health of sync client-side
    code.
  </summary>
  <token key="StorageType">
    <variant name="Ephemeral" summary="ephemeral (in-memory)"/>
    <variant name="Persistent" summary="persistent (on-disk)"/>
  </token>
  <token key="SyncModelType" variants="SyncModelType"/>
</histogram>

<histogram name="Sync.ModelTypeCount4{SyncModelType}" units="entries"
    expires_after="2023-04-24">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts the number of entries for each model type. The count is based on
    metadata entries for the type. Recorded after sync configuration. This
    metric is used for monitoring general health of sync client-side code.
  </summary>
  <token key="SyncModelType" variants="SyncModelType"/>
</histogram>

<histogram name="Sync.ModelTypeEntityChange3{SyncModelType}"
    enum="SyncEntityChange" expires_after="2023-04-24">
  <owner>treib@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded once for every sync entity change (whenever it is commited to the
    server or updated from the server). This metric is used for monitoring
    general health of sync client-side code. Note: This is only recorded with a
    data type suffix. The base version is never recorded.
  </summary>
  <token key="SyncModelType" variants="SyncModelType"/>
</histogram>

<histogram name="Sync.ModelTypeEntityMetadataWithoutInitialSync"
    enum="SyncModelTypes" expires_after="2023-07-05">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whenever ClientTagBasedModelTypeProcessor finds entity metadata
    during ModelReadyToSync() but initial_sync_done is false.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeErrorSite{SyncModelType}"
    enum="SyncModelTypeErrorSite" expires_after="2023-04-10">
  <owner>treib@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded whenever ClientTagBasedModelTypeProcessor triggers a data type
    failure (recorded for both Start and Run failures). It distinguishes call
    sites for triggering such failures.
  </summary>
  <token key="SyncModelType" variants="SyncModelType"/>
</histogram>

<histogram name="Sync.ModelTypeIncrementalUpdateReceived" enum="SyncModelTypes"
    expires_after="2023-04-16">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts the number of incremental sync updates received by the processor, per
    datatype. Logged in the model thread prior to any filtering, and includes
    tombstones as well as regular updates.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeInitialUpdateReceived" enum="SyncModelTypes"
    expires_after="2023-06-18">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts the number of initial sync updates received by the processor, per
    datatype. Logged in the model thread prior to any filtering.
  </summary>
</histogram>

<histogram name="Sync.ModelTypeMemoryKB{SyncModelType}" units="KB"
    expires_after="2023-04-17">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Estimated memory usage by sync datatype in kilobytes. Recorded after sync
    configuration. This metric is used for monitoring general health of sync
    client-side code.
  </summary>
  <token key="SyncModelType" variants="SyncModelType"/>
</histogram>

<histogram name="Sync.ModelTypeOrphanMetadata.{Operation}"
    enum="SyncModelTypes" expires_after="2023-07-05">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whenever an orphan metadata is encountered by the
    ClientTagBasedModelTypeProcessor.
  </summary>
  <token key="Operation">
    <variant name="GetData"
        summary="This happens as a result of missing data in response from
                 GetData() call."/>
    <variant name="ModelReadyToSync"
        summary="This happens as a result of a ModelReadyToSync() call with
                 metadata batch containing entities with duplicate
                 client-tag-hashes (which indicates that all but one from
                 each equivalence class are previous orphans). The type of
                 the orphan is reported in this histogram, one for each
                 orphan."/>
    <variant name="Put"
        summary="This happens as a result of a Put() call with an entity
                 whose client-tag-hash is already tracked by the processor
                 (which indicates an orphan)."/>
  </token>
</histogram>

<histogram name="Sync.ModelTypeStoreBackendError.{Operation}"
    enum="LevelDBStatus" expires_after="2023-05-28">
  <owner>treib@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the LevelDB Status error code for ModelTypeStore {Operation}
    operations. Recorded when there is an error while communicating with the DB
    for any data type that uses the ModelTypeStore. This metric should be used
    together with Sync.DataType[Run|Start]Failures2 to figure out the root cause
    of the data type failure.
  </summary>
  <token key="Operation">
    <variant name="DeleteData"/>
    <variant name="GetStoreVersion"/>
    <variant name="Init"/>
    <variant name="ReadAllRecords"/>
    <variant name="ReadRecords"/>
    <variant name="WriteModifications"/>
  </token>
</histogram>

<histogram name="Sync.ModelTypeTimeUntilEncryptionKeyFound2{SyncModelType}"
    units="GetUpdates" expires_after="2023-10-10">
  <owner>victorvianna@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records how long it took from the moment the first update encrypted with
    this key was received by ModelTypeWorker, to the moment where the key was
    available to the Cryptographer. The time is measured by the number of
    GetUpdates cycles performed by the worker *while* the Cryptographer didn't
    have pending keys (and thus the key should have been known in theory).

    This replaced Sync.ModelTypeTimeUntilEncryptionKeyFound which used to
    measure the same time in GetUpdatesResponse-s.
  </summary>
  <token key="SyncModelType" variants="SyncModelType">
    <variant name=""/>
  </token>
</histogram>

<histogram
    name="Sync.ModelTypeUndecryptablePendingUpdatesDropped{SyncModelType}"
    units="SyncEntity" expires_after="2023-10-10">
  <owner>victorvianna@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the number of entities dropped when the data type decided that a
    certain encryption key was lost and dropped all pending updates encrypted
    with it. Future updates encrypted with such key will also be ignored by the
    data type, but those are *not* counted in this metric.
  </summary>
  <token key="SyncModelType" variants="SyncModelType">
    <variant name=""/>
  </token>
</histogram>

<histogram name="Sync.ModelTypeUpdateDrop.{Reason}" enum="SyncModelTypes"
    expires_after="2023-04-24">
  <owner>treib@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded whenever a remote update for a particular data type gets dropped
    for the following reason: {Reason}.
  </summary>
  <token key="Reason">
    <variant name="CannotGenerateStorageKey"
        summary="The bridge cannot generate a valid storage key based on the
                 entity data."/>
    <variant name="DecryptionPending"
        summary="Decryption keys are missing at the moment (it is queued for
                 later decryption which may or may not happen)."/>
    <variant name="DecryptionPendingForTooLong"
        summary="Decryption keys were missing for so long that the update was
                 ignored."/>
    <variant name="FailedToDecrypt"
        summary="Decryption is not successful (maybe the data is corrupt)."/>
    <variant name="InconsistentClientTag"
        summary="Client tag hash from the server does not match the one
                 computed by the bridge based on the entity data."/>
    <variant name="TombstoneForNonexistentInIncrementalUpdate"
        summary="It was a tombstone for an entity that does not exist
                 locally."/>
    <variant name="TombstoneInFullUpdate"
        summary="It was a tombstone in a full update."/>
  </token>
</histogram>

<histogram
    name="Sync.NonReflectionUpdateFreshnessPossiblySkewed2{SyncModelType}"
    units="ms" expires_after="2023-04-24">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Freshness of the sync data per received sync entity update, excluding
    reflections. The time represents the clock difference from the model being
    modified (usually on another device) until the change is processing by this
    instance of the browser. The time is capped at 1 week. Beware of potential
    clock skew due to two clients being involved.
  </summary>
  <token key="SyncModelType" variants="SyncModelType">
    <variant name="" summary="Any type"/>
  </token>
</histogram>

<histogram name="Sync.PassphraseType" enum="SyncPassphraseType"
    expires_after="2023-06-25">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>The active sync passphrase type at sync startup.</summary>
</histogram>

<histogram name="Sync.PassphraseType2" enum="SyncPassphraseType2"
    expires_after="never">
<!-- expires-never: important for UMA filtering. -->

  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>Sync passphrase type collected at each metrics upload.</summary>
</histogram>

<histogram name="Sync.PassphraseTypeUponNotMyBirthdayOrEncryptionObsolete"
    enum="SyncPassphraseType" expires_after="2023-06-25">
  <owner>mastiz@chromium.org</owner>
  <owner>mmoskvitin@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    The active sync passphrase type when the client receives a NOT_MY_BIRTHDAY
    or ENCRYPTION_OBSOLETE event from the server.
  </summary>
</histogram>

<histogram name="Sync.PasswordNotesStateInUpdate"
    enum="SyncPasswordNotesStateInUpdate" expires_after="2023-06-04">
  <owner>mamir@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether password notes are set in password specifics proto or the
    backup field. Recorded when decrypting password entity update upon download
    from the sync server.
  </summary>
</histogram>

<histogram name="Sync.PendingInvalidationStatus"
    enum="PendingInvalidationStatus" expires_after="2023-07-02">
  <owner>shabdan@google.com</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Number of acknowledged and dropped invalidations broken down by reason.
    Recorded during browser shutdown, after a sync cycle or on incoming
    invalidation.
  </summary>
</histogram>

<histogram name="Sync.PostedClientToServerMessage"
    enum="SyncClientToServerMessageContents" expires_after="2023-07-02">
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Number of network requests issued by sync to the sync server, grouped by
    content type.
  </summary>
</histogram>

<histogram name="Sync.PostedClientToServerMessageError2" enum="SyncErrorType"
    expires_after="2023-07-02">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    A sync error code received from the sync server as a result of a
    client-initiated request. Note that this excludes network errors (e.g.
    client offline) and HTTP errors.
  </summary>
</histogram>

<histogram name="Sync.PostedClientToServerMessageLatency" units="ms"
    expires_after="2023-05-27">
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Time taken for a client-initiated request to be sent over the network and
    receive the response from the sync server.
  </summary>
</histogram>

<histogram name="Sync.PostedDataTypeCommitRequest" enum="SyncModelTypes"
    expires_after="2023-06-04">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Emitted per network Commit() request to the sync server and datatype. It
    helps estimate how much load each datatype puts on the server. Note that the
    sum across buckets does not represent the total number of requests sent to
    the server, since multiple datatypes can be grouped in a single request. See
    Sync.PostedClientToServerMessage for the total number of requests/messages.
  </summary>
</histogram>

<histogram name="Sync.PostedDataTypeGetUpdatesRequest" enum="SyncModelTypes"
    expires_after="2023-06-04">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Emitted per network GetUpdates() request to the sync server and datatype. It
    represents how much load each datatype puts on the server. Note that the sum
    across buckets does not represent the total number of requests sent to the
    server, since multiple datatypes can be grouped in a single request. See
    Sync.PostedClientToServerMessage for the total number of requests/messages.
  </summary>
</histogram>

<histogram name="Sync.PostedGetUpdatesOrigin" enum="SyncGetUpdatesOrigin"
    expires_after="2023-05-27">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Emitted per network GetUpdates() request to the sync server, it represents
    the reason for sending such GetUpdates() request.
  </summary>
</histogram>

<histogram name="Sync.ProblematicServerSideBookmarks"
    enum="RemoteBookmarkUpdateError" expires_after="2023-11-25">
  <owner>mastiz@chromium.org</owner>
  <owner>rushans@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records different issues encountered when processing incremental bookmark
    updates from the sync server.
  </summary>
</histogram>

<histogram name="Sync.ProblematicServerSideBookmarksDuringMerge"
    enum="RemoteBookmarkUpdateError" expires_after="2023-11-25">
  <owner>rushans@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records different issues encountered when processing remote bookmarks from
    the sync server during the initial merge procedure.
  </summary>
</histogram>

<histogram name="Sync.RecordedUserEventType" enum="SyncUserEventType"
    expires_after="2023-05-07">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    For every user event that is recorded, this histogram records the type of
    event (i.e. which of the &quot;oneof event&quot; entries in the
    UserEventSpecifics proto was set).
  </summary>
</histogram>

<histogram name="Sync.RedundantInvalidationPerModelType2" enum="SyncModelTypes"
    expires_after="2023-03-19">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded whenever Sync receives an invalidation with a non-fresh version,
    i.e. a smaller version number than Sync already knew about. The recorded
    value is the data type of the invalidation.
  </summary>
</histogram>

<histogram name="Sync.ResetEngineReason" enum="SyncResetEngineReason"
    expires_after="2023-06-04">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded whenever the sync engine is restarted. The recorded value is the
    calling site of ResetEngine.
  </summary>
</histogram>

<histogram name="Sync.SharingMessage.CommitResult"
    enum="SyncSharingMessageCommitErrorCode" expires_after="2023-06-04">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts the number of commit results while committing sharing message.
  </summary>
</histogram>

<histogram name="Sync.Startup.DeferredInitTrigger"
    enum="SyncDeferredInitTrigger" expires_after="2023-08-28">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>The type of event that triggered sync initialization.</summary>
</histogram>

<histogram name="Sync.Startup.PolicyLoadStartupDelay" units="ms"
    expires_after="2022-10-17">
  <obsolete>
    Expired in M108.
  </obsolete>
  <owner>ydago@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    The time spent waiting for policies to load before starting the sync engine.
    This is recorded every time the sync engine is started after having to wait
    for the browser policies from all sources to be loaded. In case the policy
    service already had all of its policies loaded by the time the sync ending
    starts, this records base::TimeDelta().
  </summary>
</histogram>

<histogram name="Sync.Startup.PolicyLoadTimeout2" enum="BooleanTimedOut"
    expires_after="2022-10-17">
  <obsolete>
    Expired in M108.
  </obsolete>
  <owner>ydago@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records if the policy load delay before starting the sync engine was timed
    out. In case of a timeout, the sync engine attempts to start ignoring
    potential policy restrictions.
  </summary>
</histogram>

<histogram name="Sync.Startup.TimeDeferred2" units="ms"
    expires_after="2023-06-16">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded on browser startup if the SyncEngine initialization is deferred by
    a fixed (configurable) delay due to performance reasons. In some cases, a
    data type may force sync to start before the delay finishes, causing the
    recorded time to be smaller. This histogram records the time spent after the
    SyncServiceImpl *creation* but before the SyncEngine initialization.
  </summary>
</histogram>

<histogram name="Sync.StopSource" enum="SyncStopSource"
    expires_after="2023-06-18">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Tracks how sync was turned off. Logged every time sync is told to stop
    permanently by the user (e.g. it won't come back on by itself).
  </summary>
</histogram>

<histogram name="Sync.SyncedHistoryFaviconAvailability.{RequestOrigin}"
    enum="FaviconAvailabilityStatus" expires_after="2023-07-10">
  <owner>victorvianna@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the availability status (local, sync or non-available) for favicons
    associated with synced history entries. Recorded when one of the following
    is displayed: entries in chrome://history that are known to be present in
    remote history data; all entries in chrome://history/syncedTabs; tabs from
    other devices in the 3 dots history menu (desktop); tabs from other devices
    in the android Recent Tabs UI.
  </summary>
  <token key="RequestOrigin">
    <variant name="HISTORY" summary="Request made by chrome://history."/>
    <variant name="RECENTLY_CLOSED_TABS"
        summary="Request made by the recently closed tabs menu."/>
    <variant name="SYNCED_TABS"
        summary="Request made by chrome://history/syncedTabs."/>
  </token>
</histogram>

<histogram name="Sync.SyncErrorInfobarDisplayed" enum="SyncErrorInfobarTypes"
    expires_after="2023-06-25">
  <owner>jlebel@chromium.org</owner>
  <owner>chrome-signin-team@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Enumeration of error conditions that displays an infobar to the user. iOS
    only.
  </summary>
</histogram>

<histogram name="Sync.SyncEverything2" enum="Boolean"
    expires_after="2023-06-18">
  <owner>treib@chromium.org</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Boolean histogram for whether the &quot;Sync Everything&quot; option was
    selected by the user. Samples are taken every time the Sync data types are
    (re)configured, which typically happens during startup and when the user
    changes any Sync settings.
  </summary>
</histogram>

<histogram name="Sync.SyncEverythingOS" enum="Boolean"
    expires_after="2023-08-12">
  <owner>mmoskvitin@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Analogous to Sync.SyncEverything2 for Chrome OS sync settings. Reflects
    whether the &quot;Sync Everything&quot; option was selected by the user for
    OS datatypes. Samples are taken every time the Sync data types are
    (re)configured, which typically happens during startup and when the user
    changes any Sync settings.
  </summary>
</histogram>

<histogram name="Sync.SyncStoppedReported" enum="Boolean"
    expires_after="2023-06-18">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts the number of Sync stopped events broken down by whether it was
    reported to the server. The event may be reported only if an access token
    and a birthday are not empty. Recorded when sync engine is stopped or
    disabled (it doesn't include regular browser shutdown).
  </summary>
</histogram>

<histogram name="Sync.SyncStoppedURLFetchResponse"
    enum="CombinedHttpResponseAndNetErrorCode" expires_after="2023-08-18">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts of responses (both http code and net error code) for Sync stopped
    event URL fetches. Note that requests that timed out are not covered by this
    histogram; see Sync.SyncStoppedURLFetchTimedOut for that.
  </summary>
</histogram>

<histogram name="Sync.SyncStoppedURLFetchTimedOut" enum="BooleanTimedOut"
    expires_after="2023-08-18">
  <owner>rushans@google.com</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Whether a Sync stopped event URL fetch timed out or not. Note that this
    records true on timeout and false on success, but doesn't record anything if
    the fetch failed for any other reason.
  </summary>
</histogram>

<histogram name="Sync.ThrottledAllModelTypes" enum="Boolean"
    expires_after="2024-02-12">
  <owner>victorvianna@google.com</owner>
  <owner>src/components/sync/OWNERS</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Logged when the server instructs the client to throttle all its data types.
    See also Sync.ThrottledSomeModelTypes which records a different event.

    This histogram can help explain changes in
    Sync.PostedClientToServerMessageError2::THROTTLED.
  </summary>
</histogram>

<histogram name="Sync.ThrottledSomeModelTypes" enum="SyncModelTypes"
    expires_after="2024-02-12">
  <owner>victorvianna@google.com</owner>
  <owner>src/components/sync/OWNERS</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Logged when the sync server instructs this client to throttle a special list
    of data types. See also Sync.ThrottledAllModelTypes which records a
    different event.

    This histogram can help explain changes in
    Sync.PostedClientToServerMessageError2::THROTTLED.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultAccessTokenFetchSuccess" enum="Boolean"
    expires_after="2023-05-27">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether access token fetching attempt was successful upon every
    request to Security Domains service.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultAddKeysAttemptIsSuccessful" enum="Boolean"
    expires_after="2023-06-18">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether attempt of adding trusted vault keys was successful (i.e.
    whether pending keys state resolved).
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultDegradedRecoverabilityValue2"
    enum="TrustedVaultDegradedRecoverabilityValue" expires_after="2023-07-09">
  <owner>mmrashad@google.com</owner>
  <owner>mmoskvitin@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the known degraded recoverability value when the degraded
    recoverability handler is started. Note that the value reflects state
    restored from the file and recorded before sending new request to the
    server.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultDeviceRegistered" enum="Boolean"
    expires_after="2023-06-18">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Simplified version of Sync.TrustedVaultDeviceRegistrationState. Records
    whether the local device is registered (and ignores whether re-registration
    was completed/pending/in-flight) upon startup (if signed in) or upon first
    signin.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultDeviceRegistrationState"
    enum="TrustedVaultDeviceRegistrationState" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether the local device is registered on the server upon startup
    (if signed in) or upon first signin, and if not registered, provides
    insights into why.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultDownloadKeysStatus"
    enum="TrustedVaultDownloadKeysStatus" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the result of an attempt to download trusted vault keys from the
    server (includes all registration versions).
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultDownloadKeysStatusV1"
    enum="TrustedVaultDownloadKeysStatus" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the result of an attempt to download trusted vault keys from the
    server, specifically if the local device is known to have a V1 registration.
  </summary>
</histogram>

<histogram
    name="Sync.TrustedVaultErrorShownOnStartup{TrustedVaultTimeSinceMigrationSuffix}"
    enum="Boolean" expires_after="2023-07-15">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether user action was required to fetch trusted vault keys upon
    startup. Recorded only if trusted vault passphrase type is used and at most
    once per browser/profile lifetime.

    {TrustedVaultTimeSinceMigrationSuffix}
  </summary>
  <token key="TrustedVaultTimeSinceMigrationSuffix"
      variants="TrustedVaultTimeSinceMigrationSuffix"/>
</histogram>

<histogram name="Sync.TrustedVaultFetchedKeysCount" units="keys"
    expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records number of trusted vault keys fetched upon fetching completion.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultFetchKeysAttempt"
    enum="TrustedVaultFetchKeysAttempt" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>Recorded when fetching trusted vault keys is attempted.</summary>
</histogram>

<histogram name="Sync.TrustedVaultFileReadStatus"
    enum="TrustedVaultFileReadStatus" expires_after="2023-06-11">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>Recorded when reading local trusted vault file.</summary>
</histogram>

<histogram name="Sync.TrustedVaultFileWriteSuccess" enum="Boolean"
    expires_after="2023-06-11">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether writing local trusted vault file upon each write.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultHintDegradedRecoverabilityChangedReason2"
    enum="TrustedVaultHintDegradedRecoverabilityChangedReason"
    expires_after="2023-04-09">
  <owner>mmrashad@google.com</owner>
  <owner>mmoskvitin@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded when an immediate degraded recoverability request is going to be
    sent to the server. Records which heuristic triggered immediate request of
    the current degraded recoverability state from the server.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultJavascriptAddRecoveryMethodSucceeded"
    enum="BooleanSuccess" expires_after="2023-06-18">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether invocations to the Javascript API
    chrome.addTrustedSyncEncryptionRecoveryMethod() completed successfully.
    Instrumented on Android only.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultJavascriptAddRecoveryMethodUserKnown"
    enum="BooleanKnown" expires_after="2023-06-18">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether invocations to the Javascript API
    chrome.addTrustedSyncEncryptionRecoveryMethod() specify a user ID that is
    known by IdentityManager. Instrumented on Android only.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultJavascriptAddRecoveryMethodValidArgs"
    enum="BooleanValid" expires_after="2023-06-18">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records invocations to the Javascript API
    chrome.addTrustedSyncEncryptionRecoveryMethod() and whether the passed
    arguments could be successfully parsed (which doesn't imply the function
    actually succeeded).
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultKeyRetrievalTrigger"
    enum="TrustedVaultUserActionTrigger" expires_after="2023-06-11">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded when user clicks/taps on trusted vault error button for the
    keys-missing error state. Buckets represents the UI elements which contain
    trusted vault error button.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultLocalDataDecryptionIsSuccessful"
    enum="BooleanSuccess" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether local data was successfully decrypted upon every attempt to
    read local file.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultLocalDataEncryptionIsSuccessful"
    enum="BooleanSuccess" expires_after="2023-03-19">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether local data was successfully encrypted upon every attempt to
    write local file.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultRecoverabilityDegradedFixTrigger"
    enum="TrustedVaultUserActionTrigger" expires_after="2023-07-15">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded when user clicks/taps on trusted vault error button for the
    recoverability-degraded error state. Buckets represents the UI elements
    which contain trusted vault error button.
  </summary>
</histogram>

<histogram
    name="Sync.TrustedVaultRecoverabilityDegradedOnStartup{TrustedVaultTimeSinceMigrationSuffix}"
    enum="Boolean" expires_after="2023-07-15">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records whether user action was required to improve the recoverability of
    trusted vault keys. Recorded only if trusted vault passphrase type is used,
    when keys are locally available and at most once per browser/profile
    lifetime.

    {TrustedVaultTimeSinceMigrationSuffix}
  </summary>
  <token key="TrustedVaultTimeSinceMigrationSuffix"
      variants="TrustedVaultTimeSinceMigrationSuffix"/>
</histogram>

<histogram name="Sync.TrustedVaultRecoverabilityStatusOnRequestCompletion"
    enum="TrustedVaultRecoverabilityStatus" expires_after="2023-06-18">
  <owner>mmrashad@google.com</owner>
  <owner>mmoskvitin@google.com</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the status of the degraded recoverability upon the request
    completion. Note that this is the status on the server side, which could be
    error if the request was failed.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultURLFetchResponse{Reason}"
    enum="CombinedHttpResponseAndNetErrorCode" expires_after="2023-05-01">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts of responses (both http code and net error code) for requests to the
    Trusted Vault server (aka Security Domain Service). Note that requests that
    timed out are not covered by this histogram.
  </summary>
  <token key="Reason">
    <variant name="" summary="Any reason"/>
    <variant name=".DownloadIsRecoverabilityDegraded"
        summary="Downloading of the recoverability-degraded state"/>
    <variant name=".DownloadKeys" summary="Downloading of keys"/>
    <variant name=".RegisterDevice" summary="Local device registration"/>
    <variant name=".RegisterUnspecifiedAuthenticationFactor"
        summary="Registration of an authentication factor of unspecified type"/>
  </token>
</histogram>

<histogram name="Sync.TrustedVaultVerifyDeviceRegistrationState"
    enum="TrustedVaultDownloadKeysStatus" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the result of verifying the state of the local device registration,
    which is achieved by simulating a key-download procedure. Recorded only for
    already-registered devices (V0 or V1) that have a primary account set, 10
    seconds after metric Sync.TrustedVaultDeviceRegistrationState is recorded.
  </summary>
</histogram>

<histogram name="Sync.TrustedVaultVerifyDeviceRegistrationStateV1"
    enum="TrustedVaultDownloadKeysStatus" expires_after="2023-06-04">
  <owner>mmoskvitin@google.com</owner>
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Records the result of verifying the state of the local device registration,
    which is achieved by simulating a key-download procedure. Recorded only for
    V1-registered devices that have a primary account set, 10 seconds after
    metric Sync.TrustedVaultDeviceRegistrationState is recorded.
  </summary>
</histogram>

<histogram name="Sync.TypedURLDatabaseError" enum="SyncTypedUrlDatabaseError"
    expires_after="2023-06-18">
  <owner>mastiz@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Recorded when TypedURLSyncBridge encounters a database error. As a result,
    the bridge stops operating (and tracking metadata) for the rest of the
    runtime of Chrome.
  </summary>
</histogram>

<histogram name="Sync.URLFetchResponse"
    enum="CombinedHttpResponseAndNetErrorCode" expires_after="2023-06-11">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Counts of responses (both http code and net error code) for Sync URL
    fetches. Note that requests that timed out are not covered by this
    histogram; see Sync.URLFetchTimedOut for that.
  </summary>
</histogram>

<histogram name="Sync.URLFetchTimedOut" enum="BooleanTimedOut"
    expires_after="2023-06-18">
  <owner>mastiz@chromium.org</owner>
  <owner>treib@chromium.org</owner>
  <component>Services&gt;Sync</component>
  <summary>
    Whether a URL fetch timed out or not. Timing out implies the fetch was
    stalled for an unknown reason. Note that this records true on timeout and
    false on success, but doesn't record anything if the fetch failed for any
    other reason.
  </summary>
</histogram>

</histograms>

</histogram-configuration>