[GCM] Fixing the initialization of last checkin/fetch time if they are

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 292c2f27ae7d1706144ba300f07e18bc5c264c7f..636b4becea51e33286a180f96c410688915a4e89 100644
--- a/google_apis/gcm/engine/gcm_store_impl.h
+++ b/google_apis/gcm/engine/gcm_store_impl.h
@@ -95,6 +95,11 @@ class GCM_EXPORT GCMStoreImpl : public GCMStore {
   void SetLastTokenFetchTime(const base::Time& time,
                              const UpdateCallback& callback) override;
 
+  // Injects a value to database. Only to be used for testing.
+  void SetValueForTesting(const std::string& key,
+                          const std::string& value,
+                          const UpdateCallback& callback);
+
  private:
   typedef std::map<std::string, int> AppIdToMessageCountMap;