components: Introduce AlarmTimer class and use it for GCM heartbeat

google_apis/gcm/engine/heartbeat_manager.h

Index: google_apis/gcm/engine/heartbeat_manager.h
diff --git a/google_apis/gcm/engine/heartbeat_manager.h b/google_apis/gcm/engine/heartbeat_manager.h
index 9266b98c8d4b21f02935002cd106dd314c27e40a..48cc6a49fe4fb0566cca1dea396c2b7b39b3336e 100644
--- a/google_apis/gcm/engine/heartbeat_manager.h
+++ b/google_apis/gcm/engine/heartbeat_manager.h
@@ -7,10 +7,14 @@
 
 #include "base/callback.h"
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "base/timer/timer.h"
 #include "google_apis/gcm/base/gcm_export.h"
 
+namespace base {
+class Timer;
+}
+
 namespace mcs_proto {
 class HeartbeatConfig;
 }
@@ -65,8 +69,8 @@ class GCM_EXPORT HeartbeatManager {
   // provided).
   int server_interval_ms_;
 
-  // Timer for triggering heartbeats.
-  base::Timer heartbeat_timer_;
+  // Timer for triggering heartbeats.  Owned by HeartbeatManager.

[Nicolas Zea, 2014/10/21 17:57:54]

nit: Since you're using a scoped_ptr now, ownership is implied. No need for the
comment.

[Chirantan Ekbote, 2014/10/21 21:13:48]

Done.

+  scoped_ptr<base::Timer> heartbeat_timer_;
 
   // Callbacks for interacting with the the connection.
   base::Closure send_heartbeat_callback_;