[GCM] Adding last token fetching time handling

components/gcm_driver/fake_gcm_driver.cc

Index: components/gcm_driver/fake_gcm_driver.cc
diff --git a/components/gcm_driver/fake_gcm_driver.cc b/components/gcm_driver/fake_gcm_driver.cc
index 73b53d903389cd1e5462093f03ad78bdb5e3e091..21416a5946708177ba1731b586d1198d5ee7ca2b 100644
--- a/components/gcm_driver/fake_gcm_driver.cc
+++ b/components/gcm_driver/fake_gcm_driver.cc
@@ -90,4 +90,11 @@ void FakeGCMDriver::UpdateAccountMapping(
 void FakeGCMDriver::RemoveAccountMapping(const std::string& account_id) {
 }
 
+base::Time FakeGCMDriver::GetLastTokenFetchTime() {
+  return base::Time();
+}
+
+void FakeGCMDriver::SetLastTokenFetchTime(const base::Time& time) {
+}
+
 }  // namespace gcm