[GCM] Adding last token fetching time handling

google_apis/gcm/engine/gcm_store_impl.h

Index: google_apis/gcm/engine/gcm_store_impl.h
diff --git a/google_apis/gcm/engine/gcm_store_impl.h b/google_apis/gcm/engine/gcm_store_impl.h
index 283b920f08d58a57033fcbb6a53f7b36c6b24ba2..292c2f27ae7d1706144ba300f07e18bc5c264c7f 100644
--- a/google_apis/gcm/engine/gcm_store_impl.h
+++ b/google_apis/gcm/engine/gcm_store_impl.h
@@ -91,6 +91,10 @@ class GCM_EXPORT GCMStoreImpl : public GCMStore {
   void RemoveAccountMapping(const std::string& account_id,
                             const UpdateCallback& callback) override;
 
+  // Sets last token fetch time.
+  void SetLastTokenFetchTime(const base::Time& time,
+                             const UpdateCallback& callback) override;
+
  private:
   typedef std::map<std::string, int> AppIdToMessageCountMap;