[StopSyncInPausedState] Clear UserEvent data when sync is stopped

With disabled kStopSyncInPausedState UserEvent data isn't recorded due
to UserEventModelTypeController::GetPreconditionState(), but it doesn't
work if sync completely stopped.

This CL adds UserEventModelTypeController::Stop() similar to what we
have for autofill datatypes, which treats STOP_SYNC as DISABLE_SYNC.

The behavior already covered by
SingleClientUserEventsSyncTest.ShouldNotUploadInSyncPausedState.

Bug: 906995
Change-Id: I2a3e68ca91082a6933ca3bf673d225a9f93ceaa1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2091491Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Cr-Commit-Position: refs/heads/master@{#748182}

components/sync_user_events/user_event_model_type_controller.cc

@@ -28,12 +28,28 @@ UserEventModelTypeController::~UserEventModelTypeController() {
   sync_service_->RemoveObserver(this);
 }
 
+void UserEventModelTypeController::Stop(syncer::ShutdownReason shutdown_reason,
+                                        StopCallback callback) {
+  DCHECK(CalledOnValidThread());
+  switch (shutdown_reason) {
+    case syncer::STOP_SYNC:
+      // Special case: For USER_EVENT, we want to clear all data even when Sync
+      // is stopped temporarily.
+      shutdown_reason = syncer::DISABLE_SYNC;
+      break;
+    case syncer::DISABLE_SYNC:
+    case syncer::BROWSER_SHUTDOWN:
+      break;
+  }
+  ModelTypeController::Stop(shutdown_reason, std::move(callback));
+}
+
 DataTypeController::PreconditionState
 UserEventModelTypeController::GetPreconditionState() const {
   if (sync_service_->GetUserSettings()->IsUsingSecondaryPassphrase()) {
     return PreconditionState::kMustStopAndClearData;
   }
-  // TODO(crbug.com/906995): Remove the syncer::IsWebSignout() check once we
+  // TODO(crbug.com/938819): Remove the syncer::IsWebSignout() check once we
   // stop sync in this state. Also remove the "+google_apis/gaia" include
   // dependency and the "//google_apis" build dependency of sync_user_events.
   if (syncer::IsWebSignout(sync_service_->GetAuthError())) {

components/sync_user_events/user_event_model_type_controller.h

@@ -25,6 +25,7 @@ class UserEventModelTypeController : public syncer::ModelTypeController,
   ~UserEventModelTypeController() override;
 
   // syncer::DataTypeController implementation.
+  void Stop(ShutdownReason shutdown_reason, StopCallback callback) override;
   PreconditionState GetPreconditionState() const override;
 
   // syncer::SyncServiceObserver implementation.