[cc] Remove BeginFrameAck from BFS::DidFinishFrame and update tests.

cc/surfaces/primary_begin_frame_source.cc

 // Copyright 2017 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/surfaces/primary_begin_frame_source.h"
 
 namespace cc {
 
 PrimaryBeginFrameSource::PrimaryBeginFrameSource()
     : begin_frame_source_(this) {}
@@ skipping 34 matching lines @@
   begin_frame_source_.OnBeginFrame(args);
   last_begin_frame_args_ = args;
 }
 
 const BeginFrameArgs& PrimaryBeginFrameSource::LastUsedBeginFrameArgs() const {
   return last_begin_frame_args_;
 }
 
 void PrimaryBeginFrameSource::OnBeginFrameSourcePausedChanged(bool paused) {}
 
-void PrimaryBeginFrameSource::DidFinishFrame(BeginFrameObserver* obs,
-                                             const BeginFrameAck& ack) {
-  begin_frame_source_.DidFinishFrame(obs, ack);
+void PrimaryBeginFrameSource::DidFinishFrame(BeginFrameObserver* obs) {
+  begin_frame_source_.DidFinishFrame(obs);
 }
 
 void PrimaryBeginFrameSource::AddObserver(BeginFrameObserver* obs) {
   begin_frame_source_.AddObserver(obs);
 }
 
 void PrimaryBeginFrameSource::RemoveObserver(BeginFrameObserver* obs) {
   begin_frame_source_.RemoveObserver(obs);
 }
 
@@ skipping 10 matching lines @@
   if (!current_begin_frame_source_)
     return;
 
   if (needs_begin_frames_)
     current_begin_frame_source_->AddObserver(this);
   else
     current_begin_frame_source_->RemoveObserver(this);
 }
 
 }  // namespace cc