[GCM] Extracting GCMConnectionObserver from GCMAppHandler

components/gcm_driver/gcm_driver_desktop.h

Index: components/gcm_driver/gcm_driver_desktop.h
diff --git a/components/gcm_driver/gcm_driver_desktop.h b/components/gcm_driver/gcm_driver_desktop.h
index 8eba9683961033c3b9c58f1d553ed9cbc1b9be52..04bc22d15a9832934e833f50b3e1ac3d12cfa6c1 100644
--- a/components/gcm_driver/gcm_driver_desktop.h
+++ b/components/gcm_driver/gcm_driver_desktop.h
@@ -14,7 +14,9 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "components/gcm_driver/gcm_client.h"
+#include "components/gcm_driver/gcm_connection_observer.h"
 #include "components/gcm_driver/gcm_driver.h"
 
 namespace base {
@@ -55,6 +57,9 @@ class GCMDriverDesktop : public GCMDriver {
   virtual void AddAppHandler(const std::string& app_id,
                              GCMAppHandler* handler) OVERRIDE;
   virtual void RemoveAppHandler(const std::string& app_id) OVERRIDE;
+  virtual void AddConnectionObserver(GCMConnectionObserver* observer) OVERRIDE;
+  virtual void RemoveConnectionObserver(
+      GCMConnectionObserver* observer) OVERRIDE;
   virtual void Enable() OVERRIDE;
   virtual void Disable() OVERRIDE;
   virtual GCMClient* GetGCMClientForTesting() const OVERRIDE;
@@ -134,6 +139,10 @@ class GCMDriverDesktop : public GCMDriver {
   // it may be out of date while connection changes are happening.
   bool connected_;
 
+  // List of observers to notify when connection state changes.
+  // Makes sure list is empty on destruction.
+  ObserverList<GCMConnectionObserver, true> connection_observer_list_;
+
   scoped_refptr<base::SequencedTaskRunner> ui_thread_;
   scoped_refptr<base::SequencedTaskRunner> io_thread_;