Push API: Validate storage before returning cached subscriptions

components/gcm_driver/fake_gcm_driver.h

Index: components/gcm_driver/fake_gcm_driver.h
diff --git a/components/gcm_driver/fake_gcm_driver.h b/components/gcm_driver/fake_gcm_driver.h
index 9ec1567d6182818a11fe42201f676cd7bdb1f9c2..131802e2f9a9de716716a4e3a0d41107f464d2d2 100644
--- a/components/gcm_driver/fake_gcm_driver.h
+++ b/components/gcm_driver/fake_gcm_driver.h
@@ -25,6 +25,11 @@ class FakeGCMDriver : public GCMDriver {
   ~FakeGCMDriver() override;
 
   // GCMDriver overrides:
+  void ValidateRegistration(
+      const std::string& app_id,
+      const std::vector<std::string>& sender_ids,
+      const std::string& registration_id,
+      const ValidateRegistrationCallback& callback) override;
   void OnSignedIn() override;
   void OnSignedOut() override;
   void AddConnectionObserver(GCMConnectionObserver* observer) override;