Add support for GCM subtypes to desktop Instance ID implementation

components/gcm_driver/fake_gcm_client.cc

Index: components/gcm_driver/fake_gcm_client.cc
diff --git a/components/gcm_driver/fake_gcm_client.cc b/components/gcm_driver/fake_gcm_client.cc
index 8c6ec7c91227ed88f9fd56513f2c6d027cc64d66..c868e9cea34927668209761370048f241dfa216e 100644
--- a/components/gcm_driver/fake_gcm_client.cc
+++ b/components/gcm_driver/fake_gcm_client.cc
@@ -80,6 +80,7 @@ void FakeGCMClient::Initialize(
         url_request_context_getter,
     std::unique_ptr<Encryptor> encryptor,
     Delegate* delegate) {
+  category_for_subtypes_ = chrome_build_info.category_for_subtypes;
   delegate_ = delegate;
 }
 
@@ -220,6 +221,10 @@ void FakeGCMClient::GetInstanceIDData(const std::string& app_id,
   *extra_data = iter->second.second;
 }
 
+bool FakeGCMClient::CategoryHasSubtype(const std::string& category) {
+  return category == category_for_subtypes_;
+}
+
 void FakeGCMClient::AddHeartbeatInterval(const std::string& scope,
                                          int interval_ms) {
 }