Fold BeginFrameSource::SetClientReady into AddObserver

cc/test/fake_external_begin_frame_source.cc

 // Copyright 2014 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/fake_external_begin_frame_source.h"
 
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "cc/test/begin_frame_args_test.h"
 
 namespace cc {
 
 FakeExternalBeginFrameSource::FakeExternalBeginFrameSource(double refresh_rate)
     : milliseconds_per_frame_(1000.0 / refresh_rate),
-      is_ready_(false),
       weak_ptr_factory_(this) {
   DetachFromThread();
 }
 
 FakeExternalBeginFrameSource::~FakeExternalBeginFrameSource() {
   DCHECK(CalledOnValidThread());
 }
 
-void FakeExternalBeginFrameSource::SetClientReady() {
-  DCHECK(CalledOnValidThread());
-  is_ready_ = true;
-}
-
 void FakeExternalBeginFrameSource::OnNeedsBeginFramesChanged(
     bool needs_begin_frames) {
   DCHECK(CalledOnValidThread());
   if (needs_begin_frames) {
     PostTestOnBeginFrame();
   } else {
     begin_frame_task_.Cancel();
   }
 }
 
 void FakeExternalBeginFrameSource::TestOnBeginFrame() {
   DCHECK(CalledOnValidThread());
   CallOnBeginFrame(CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE));
   PostTestOnBeginFrame();
 }
 
 void FakeExternalBeginFrameSource::PostTestOnBeginFrame() {
   begin_frame_task_.Reset(
       base::Bind(&FakeExternalBeginFrameSource::TestOnBeginFrame,
                  weak_ptr_factory_.GetWeakPtr()));
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE, begin_frame_task_.callback(),
       base::TimeDelta::FromMilliseconds(milliseconds_per_frame_));
 }
 
 }  // namespace cc