[GCM] Exposing persistence of account mappings in GCM Driver

components/gcm_driver/gcm_driver_android.cc

Index: components/gcm_driver/gcm_driver_android.cc
diff --git a/components/gcm_driver/gcm_driver_android.cc b/components/gcm_driver/gcm_driver_android.cc
index ae643cd66072904bef8a32c81c44af4a5ea2bd7f..a6ab94a88f08624dfd6c0d5f38076a7c52521000 100644
--- a/components/gcm_driver/gcm_driver_android.cc
+++ b/components/gcm_driver/gcm_driver_android.cc
@@ -129,6 +129,13 @@ void GCMDriverAndroid::SetGCMRecording(const GetGCMStatisticsCallback& callback,
   NOTIMPLEMENTED();
 }
 
+void GCMDriverAndroid::UpdateAccountMapping(
+    const AccountMapping& account_mapping) {
+}
+
+void GCMDriverAndroid::RemoveAccountMapping(const std::string& account_id) {
+}
+
 GCMClient::Result GCMDriverAndroid::EnsureStarted() {
   // TODO(johnme): Maybe we should check if GMS is available?
   return GCMClient::SUCCESS;