Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/policy/cloud_policy_subsystem.h

Index: chrome/browser/policy/cloud_policy_subsystem.h
diff --git a/chrome/browser/policy/cloud_policy_subsystem.h b/chrome/browser/policy/cloud_policy_subsystem.h
index fd81072387e2f8ed8fd674545cbf52645e0e3033..2ff3eab2921f581b2f2578670d834ceb11affce6 100644
--- a/chrome/browser/policy/cloud_policy_subsystem.h
+++ b/chrome/browser/policy/cloud_policy_subsystem.h
@@ -7,7 +7,7 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
-#include "content/public/browser/notification_observer.h"
+#include "base/prefs/public/pref_observer.h"
 #include "net/base/network_change_notifier.h"
 
 class PrefService;
@@ -25,7 +25,7 @@ class PolicyNotifier;
 // policy. It glues together the backend, the policy controller and manages the
 // life cycle of the policy providers.
 class CloudPolicySubsystem
-    : public content::NotificationObserver,
+    : public PrefObserver,
       public net::NetworkChangeNotifier::IPAddressObserver {
  public:
   enum PolicySubsystemState {
@@ -131,10 +131,9 @@ class CloudPolicySubsystem
   virtual void CreateDeviceTokenFetcher();
   virtual void CreateCloudPolicyController();
 
-  // content::NotificationObserver overrides.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // PrefObserver overrides.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
 
   // net::NetworkChangeNotifier::IPAddressObserver:
   virtual void OnIPAddressChanged() OVERRIDE;