Split PrefService into PrefService, PrefServiceSimple and PrefServiceSyncable.

chrome/browser/task_manager/task_manager.h

Index: chrome/browser/task_manager/task_manager.h
diff --git a/chrome/browser/task_manager/task_manager.h b/chrome/browser/task_manager/task_manager.h
index 5ac34c4b9c7188d9a4f5b92b441d2599c1a2cf29..7e6de3fc7ec83cddde01cebc60e2a89e533bacfe 100644
--- a/chrome/browser/task_manager/task_manager.h
+++ b/chrome/browser/task_manager/task_manager.h
@@ -21,6 +21,7 @@
 #include "content/public/common/gpu_memory_stats.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCache.h"
 
+class PrefServiceSimple;
 class TaskManagerModel;
 class TaskManagerModelGpuDataManagerObserver;
 
@@ -184,7 +185,7 @@ class TaskManager {
     virtual ~ResourceProvider() {}
   };
 
-  static void RegisterPrefs(PrefService* prefs);
+  static void RegisterPrefs(PrefServiceSimple* prefs);
 
   // Returns true if the process at the specified index is the browser process.
   bool IsBrowserProcess(int index) const;