Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/browser_process_impl.h

Index: chrome/browser/browser_process_impl.h
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index 45f6b35f00e8cb8f22cbf5e8dda97b7bad29e112..d7c3cc712331105aca9dd41f643dada4a1912931 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -17,11 +17,11 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/timer.h"
 #include "chrome/browser/api/prefs/pref_member.h"
 #include "chrome/browser/browser_process.h"
-#include "content/public/browser/notification_observer.h"
 
 class ChromeNetLog;
 class ChromeResourceDispatcherHostDelegate;
@@ -44,7 +44,7 @@ class PolicyService;
 // Real implementation of BrowserProcess that creates and returns the services.
 class BrowserProcessImpl : public BrowserProcess,
                            public base::NonThreadSafe,
-                           public content::NotificationObserver {
+                           public PrefObserver {
  public:
   // |local_state_task_runner| must be a shutdown-blocking task runner.
   BrowserProcessImpl(base::SequencedTaskRunner* local_state_task_runner,
@@ -122,10 +122,9 @@ class BrowserProcessImpl : public BrowserProcess,
   virtual CRLSetFetcher* crl_set_fetcher() OVERRIDE;
   virtual BookmarkPromptController* bookmark_prompt_controller() OVERRIDE;
 
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
 
  private:
   void CreateMetricsService();