Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/webui/options/preferences_browsertest.h

Index: chrome/browser/ui/webui/options/preferences_browsertest.h
diff --git a/chrome/browser/ui/webui/options/preferences_browsertest.h b/chrome/browser/ui/webui/options/preferences_browsertest.h
index 1caa410733d7d78d336af7ed116d18abe3627c47..25d14b09c5276ca87416f55639d91a482aab4a33 100644
--- a/chrome/browser/ui/webui/options/preferences_browsertest.h
+++ b/chrome/browser/ui/webui/options/preferences_browsertest.h
@@ -11,6 +11,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "chrome/browser/policy/mock_configuration_policy_provider.h"
 #include "chrome/browser/policy/policy_types.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ -33,7 +34,7 @@ class RenderViewHost;
 // CoreOptionsHandler and the specialized classes handling Chrome OS device and
 // proxy prefs behave correctly.
 class PreferencesBrowserTest : public InProcessBrowserTest,
-                               public content::NotificationObserver {
+                               public PrefObserver {
  public:
   PreferencesBrowserTest();
   ~PreferencesBrowserTest();
@@ -41,10 +42,9 @@ class PreferencesBrowserTest : public InProcessBrowserTest,
   // InProcessBrowserTest implementation:
   virtual void SetUpOnMainThread() 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;
 
  protected:
   MOCK_METHOD1(OnCommit, void(const PrefService::Preference*));