Add UMA data for memory pressure warning received for sync

components/sync_driver/sync_prefs.h

Index: components/sync_driver/sync_prefs.h
diff --git a/components/sync_driver/sync_prefs.h b/components/sync_driver/sync_prefs.h
index 23109467a46dc4be4d3a20a9a7934279c50cab2e..043ed734307a71c30c862c340b6c426822bf1c16 100644
--- a/components/sync_driver/sync_prefs.h
+++ b/components/sync_driver/sync_prefs.h
@@ -140,6 +140,16 @@ class SyncPrefs : NON_EXPORTED_BASE(public base::NonThreadSafe),
   // For testing.
   void SetManagedForTest(bool is_managed);
 
+  // Get/Set number of memory warnings received.
+  int GetMemoryPressureWarningCount() const;
+  void SetMemoryPressureWarningCount(int value);
+
+  // Check if the previous shutdown was clean.
+  bool DidSyncShutdownCleanly() const;
+
+  // Set whetherthe last shutdown was clean.
+  void SetCleanShutdown(bool value);
+
  private:
   void RegisterPrefGroups();