[cc] Adds source_id and sequence_number to BeginFrameArgs.

cc/test/begin_frame_source_test.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/test/begin_frame_source_test.h"
 
 #include "cc/test/begin_frame_args_test.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 17 matching lines @@
 MockBeginFrameObserver::~MockBeginFrameObserver() {}
 
 const BeginFrameArgs MockBeginFrameObserver::kDefaultBeginFrameArgs =
     CreateBeginFrameArgsForTesting(
 #ifdef NDEBUG
         nullptr,
 #else
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "MockBeginFrameObserver::kDefaultBeginFrameArgs"),
 #endif
+        0,
+        BeginFrameArgs::kStartingFrameNumber,

[brianderson, 2016/12/15 22:10:33]

Should this be "Invalid" since the rest of the values in the list correspond to
and invalid BeginFrameArgs?

[Eric Seckler, 2016/12/16 17:25:58]

I added a DCHECK to the BeginFrameArgs constructor with field values, which
verifies that the provided sequence_number is valid. I can get rid of it to
allow a "bad" sequence number here if you'd prefer that?

[brianderson, 2016/12/16 17:53:38]

This is okay as is then. Thanks for the explanation.

         -1,
         -1,
         -1);
 
 }  // namespace cc