Add UMA data for memory pressure warning received for sync

components/sync_driver/sync_prefs.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_DRIVER_SYNC_PREFS_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_PREFS_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 122 matching lines @@
   void SetFirstSyncTime(base::Time time);
   void ClearFirstSyncTime();
 
   // Out of band sync passphrase prompt getter/setter.
   bool IsPassphrasePrompted() const;
   void SetPassphrasePrompted(bool value);
 
   // For testing.
   void SetManagedForTest(bool is_managed);
 
+  int GetMemoryPressure() const;

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

Need comments for all 4 functions

[Gang Wu, 2015/05/15 21:13:47]

Done.

+  void SetMemoryPressure(int value);
+  bool IsPreviousCrashed() const;

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

These two function names are confusing. Basically they are supposed to tell
whether the last shutdown was successful. The names should reflect that clearly.

+  void SetCurrentShutdown(bool value);
+
  private:
   void RegisterPrefGroups();
 
   static void RegisterDataTypePreferredPref(
       user_prefs::PrefRegistrySyncable* prefs,
       syncer::ModelType type,
       bool is_preferred);
   bool GetDataTypePreferred(syncer::ModelType type) const;
   void SetDataTypePreferred(syncer::ModelType type, bool is_preferred);
 
@@ skipping 22 matching lines @@
   // etc.
   typedef std::map<syncer::ModelType, syncer::ModelTypeSet> PrefGroupsMap;
   PrefGroupsMap pref_groups_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncPrefs);
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_PREFS_H_