Add UMA data for memory pressure warning received for sync

chrome/browser/sync/profile_sync_service.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/profile_sync_service.h"
 
 #include <cstddef>
 #include <map>
 #include <vector>
 
@@ skipping 347 matching lines @@
   }
 
 #if defined(ENABLE_PRE_SYNC_BACKUP)
   if (!running_rollback && signin_->GetAccountIdToUse().empty()) {
     CleanUpBackup();
   }
 #else
   DCHECK(!running_rollback);
 #endif
 
+  memory_pressure_listener_.reset(new base::MemoryPressureListener(base::Bind(
+      &ProfileSyncService::OnMemoryPressure, weak_factory_.GetWeakPtr())));
   startup_controller_->Reset(GetRegisteredDataTypes());
   startup_controller_->TryStart();
 }
 
 void ProfileSyncService::TrySyncDatatypePrefRecovery() {
   DCHECK(!backend_initialized());
   if (!HasSyncSetupCompleted())
     return;
 
   // There was a bug where OnUserChoseDatatypes was not properly called on
@@ skipping 317 matching lines @@
           invalidator,
           sync_prefs_.AsWeakPtr(),
           sync_folder));
 
   // Initialize the backend.  Every time we start up a new SyncBackendHost,
   // we'll want to start from a fresh SyncDB, so delete any old one that might
   // be there.
   InitializeBackend(ShouldDeleteSyncFolder());
 
   UpdateFirstSyncTimePref();
+
+  CheckPreviousShutdownMemoryWarning();
 }
 
 void ProfileSyncService::OnGetTokenSuccess(
     const OAuth2TokenService::Request* request,
     const std::string& access_token,
     const base::Time& expiration_time) {
   DCHECK_EQ(access_token_request_, request);
   access_token_request_.reset();
   access_token_ = access_token;
   token_receive_time_ = base::Time::Now();
@@ skipping 190 matching lines @@
   encryption_pending_ = false;
   encrypt_everything_ = false;
   encrypted_types_ = syncer::SyncEncryptionHandler::SensitiveTypes();
   passphrase_required_reason_ = syncer::REASON_PASSPHRASE_NOT_REQUIRED;
   request_access_token_retry_timer_.Stop();
   // Revert to "no auth error".
   if (last_auth_error_.state() != GoogleServiceAuthError::NONE)
     UpdateAuthErrorState(GoogleServiceAuthError::AuthErrorNone());
 
   NotifyObservers();
+
+  sync_prefs_.SetCurrentShutdown(false);

[stanisc, 2015/05/15 20:31:04]

Please add comment explaining this.

[Gang Wu, 2015/05/15 21:13:46]

Done.

 }
 
 void ProfileSyncService::DisableForUser() {
   // Clear prefs (including SyncSetupHasCompleted) before shutting down so
   // PSS clients don't think we're set up while we're shutting down.
   sync_prefs_.ClearPreferences();
   ClearUnrecoverableError();
   ShutdownImpl(syncer::DISABLE_SYNC);
 }
 
@@ skipping 1788 matching lines @@
   std::string birthday;
   syncer::UserShare* user_share = GetUserShare();
   if (user_share && user_share->directory.get()) {
     birthday = user_share->directory->store_birthday();
   }
   if (!access_token_.empty() && !cache_guid.empty() && !birthday.empty()) {
     sync_stopped_reporter_->ReportSyncStopped(
         access_token_, cache_guid, birthday);
   }
 }
+
+void ProfileSyncService::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  if (memory_pressure_level ==
+      base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) {
+    sync_prefs_.SetMemoryPressure(sync_prefs_.GetMemoryPressure() + 1);

[stanisc, 2015/05/15 20:31:04]

Looking at function names, GetMemoryPressure and SetMemoryPressure, I expected
them to return some sort of pressure level. From this code it looks like these
are counters of received warnings. Consider renaming these functions to reflect
that.
How about GetMemoryPressureWarningCount and SetMemoryPressureWarningCount?

[Gang Wu, 2015/05/15 21:13:46]

Done.

+  }
+}
+
+void ProfileSyncService::CheckPreviousShutdownMemoryWarning() {
+  int warning_received = sync_prefs_.GetMemoryPressure();
+
+  if (-1 != warning_received) {
+  // -1 means it is new client

[stanisc, 2015/05/15 20:31:04]

Indent this comment and add "." at the end.

[Gang Wu, 2015/05/15 21:13:46]

Done.

+    if (sync_prefs_.IsPreviousCrashed()) {
+      UMA_HISTOGRAM_COUNTS("Sync.MemoryPressureWarningBeforeCrash",
+                           warning_received);
+    } else {
+      UMA_HISTOGRAM_COUNTS("Sync.MemoryPressureWarningwithoutCrash",

[stanisc, 2015/05/15 20:31:04]

without should start with capital W

[Gang Wu, 2015/05/15 21:13:46]

Done.

+                           warning_received);
+    }
+  }
+  sync_prefs_.SetMemoryPressure(0);
+  sync_prefs_.SetCurrentShutdown(true);
+}