components: Introduce AlarmTimer class and use it for GCM heartbeat

google_apis/gcm/engine/mcs_client.cc

Index: google_apis/gcm/engine/mcs_client.cc
diff --git a/google_apis/gcm/engine/mcs_client.cc b/google_apis/gcm/engine/mcs_client.cc
index ec156b786f8e6bbeecf574e9dc25d6e734cd1a12..34ebfcb0e6cb33441e2cf2371adac8106ff61e9b 100644
--- a/google_apis/gcm/engine/mcs_client.cc
+++ b/google_apis/gcm/engine/mcs_client.cc
@@ -7,11 +7,13 @@
 #include <set>
 
 #include "base/basictypes.h"
+#include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/time/clock.h"
 #include "base/time/time.h"
+#include "base/timer/timer.h"
 #include "google_apis/gcm/base/mcs_util.h"
 #include "google_apis/gcm/base/socket_stream.h"
 #include "google_apis/gcm/engine/connection_factory.h"
@@ -177,6 +179,10 @@ MCSClient::MCSClient(const std::string& version_string,
 MCSClient::~MCSClient() {
 }
 
+void MCSClient::SetHeartbeatTimer(scoped_ptr<base::Timer> timer) {
+  heartbeat_manager_.SetHeartbeatTimer(timer.Pass());
+}
+
 void MCSClient::Initialize(
     const ErrorCallback& error_callback,
     const OnMessageReceivedCallback& message_received_callback,