[GCM] Stop/restart GCM when the state is forced off/on

google_apis/gcm/engine/gcm_store_impl.cc

Index: google_apis/gcm/engine/gcm_store_impl.cc
diff --git a/google_apis/gcm/engine/gcm_store_impl.cc b/google_apis/gcm/engine/gcm_store_impl.cc
index 31b258f7a6c149281bbe379ef4e2f49ee82e4cae..91d3e70077bdaf1a68d03f064a65626bd7ffb84e 100644
--- a/google_apis/gcm/engine/gcm_store_impl.cc
+++ b/google_apis/gcm/engine/gcm_store_impl.cc
@@ -96,6 +96,7 @@ class GCMStoreImpl::Backend
 
   // Blocking implementations of GCMStoreImpl methods.
   void Load(const LoadCallback& callback);
+  void Close();
   void Destroy(const UpdateCallback& callback);
   void SetDeviceCredentials(uint64 device_android_id,
                             uint64 device_security_token,
@@ -213,6 +214,11 @@ void GCMStoreImpl::Backend::Load(const LoadCallback& callback) {
   return;
 }
 
+void GCMStoreImpl::Backend::Close() {
+  DVLOG(1) << "Closing GCM store.";
+  db_.reset();
+}
+
 void GCMStoreImpl::Backend::Destroy(const UpdateCallback& callback) {
   DVLOG(1) << "Destroying GCM store.";
   db_.reset();
@@ -634,6 +640,12 @@ void GCMStoreImpl::Load(const LoadCallback& callback) {
                             callback)));
 }
 
+void GCMStoreImpl::Close() {
+  blocking_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&GCMStoreImpl::Backend::Close, backend_));
+}
+
 void GCMStoreImpl::Destroy(const UpdateCallback& callback) {
   blocking_task_runner_->PostTask(
       FROM_HERE,