Add support for GCM subtypes to desktop Instance ID implementation

google_apis/gcm/engine/gcm_request_test_base.h

Index: google_apis/gcm/engine/gcm_request_test_base.h
diff --git a/google_apis/gcm/engine/gcm_request_test_base.h b/google_apis/gcm/engine/gcm_request_test_base.h
index 8781dda837a1483162b6d5d4ca0722240888dbe8..3eb384d17af3e77b59c33ac3fbb133d19a7e254e 100644
--- a/google_apis/gcm/engine/gcm_request_test_base.h
+++ b/google_apis/gcm/engine/gcm_request_test_base.h
@@ -31,6 +31,12 @@ class GCMRequestTestBase : public testing::Test {
   // It can be overridden by the test class to add additional logic.
   virtual void CompleteFetch();
 
+  // Verifies that the Fetcher's upload_data exactly matches the given
+  // properties. The map will be cleared as a side-effect. Wrap calls to this
+  // with ASSERT_NO_FATAL_FAILURE.
+  void VerifyFetcherUploadData(

[Nicolas Zea, 2016/08/17 20:54:09]

optional suggestion: it might make sense to return an AssertionResult here
instead of requiring the caller to wrap the method in an
ASSERT_NO_FATAL_FAILURE. In my mind having an AssertionResult makes it clearer
that the responsibility is on the caller to handle the result (and it also makes
it easier to trace where the failure happened). 

[johnme, 2016/08/18 17:43:21]

Hmm, on the other hand it seems that would make the implementation less clear,
since each of the 5 ASSERT_ statements would go from one line to two, and the
ASSERT_EQs would have to manually construct error strings, which is currently
handled for them automatically.
Actually, perhaps the opposite. With ASSERT_NO_FATAL_FAILURE you can nest them,
i.e. if MyTest calls ASSERT_NO_FATAL_FAILURE(Foo()) where Foo itself calls
ASSERT_NO_FATAL_FAILURE(Bar()), the error message will explain the full chain
(MyTest line -> Foo line -> Bar line -> actual assertion failure). Whereas with
ASSERT_TRUE(ReturnsAssertionResult()), you only see the outermost ASSERT_TRUE in
MyTest and the innermost error message.

+      std::map<std::string, std::string>* expected_pairs);
+
   net::URLRequestContextGetter* url_request_context_getter() const {
     return url_request_context_getter_.get();
   }