GCM: Add Android UMA, and UMA for deleted/collapsed messages

components/gcm_driver/gcm_client_impl.h

Index: components/gcm_driver/gcm_client_impl.h
diff --git a/components/gcm_driver/gcm_client_impl.h b/components/gcm_driver/gcm_client_impl.h
index edb637a7e0e8c0ac0c0501bfd59bdade3b8bb7a8..9e102154b86b20e1cbe8c7ac5d81432a36087b1f 100644
--- a/components/gcm_driver/gcm_client_impl.h
+++ b/components/gcm_driver/gcm_client_impl.h
@@ -300,6 +300,13 @@ class GCMClientImpl
       const mcs_proto::DataMessageStanza& data_message_stanza,
       MessageData& message_data);
 
+  // Fires OnMessagesDeleted event on the delegate of this class, based on the
+  // details in |data_message_stanza| and |message_data|.
+  void HandleIncomingDeletedMessages(
+      const std::string& app_id,
+      const mcs_proto::DataMessageStanza& data_message_stanza,
+      MessageData& message_data);
+
   // Fires OnMessageSendError event on the delegate of this class, based on the
   // details in |data_message_stanza| and |message_data|.
   void HandleIncomingSendError(