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

cc/scheduler/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/scheduler/begin_frame_source.h"
 
 #include <stddef.h>
 
 #include "base/atomic_sequence_num.h"
 #include "base/auto_reset.h"
@@ skipping 95 matching lines @@
 
 void BackToBackBeginFrameSource::RemoveObserver(BeginFrameObserver* obs) {
   DCHECK(obs);
   DCHECK(observers_.find(obs) != observers_.end());
   observers_.erase(obs);
   pending_begin_frame_observers_.erase(obs);
   if (pending_begin_frame_observers_.empty())
     time_source_->SetActive(false);
 }
 
-void BackToBackBeginFrameSource::DidFinishFrame(BeginFrameObserver* obs,
-                                                const BeginFrameAck& ack) {
+void BackToBackBeginFrameSource::DidFinishFrame(BeginFrameObserver* obs) {
   if (observers_.find(obs) != observers_.end()) {
     pending_begin_frame_observers_.insert(obs);
     time_source_->SetActive(true);
   }
 }
 
 bool BackToBackBeginFrameSource::IsThrottled() const {
   return false;
 }
 
@@ skipping 176 matching lines @@
   DCHECK(obs);
   DCHECK(observers_.find(obs) != observers_.end());
 
   observers_.erase(obs);
   if (observers_.empty()) {
     last_begin_frame_args_ = BeginFrameArgs();
     client_->OnNeedsBeginFrames(false);
   }
 }
 
-void ExternalBeginFrameSource::DidFinishFrame(BeginFrameObserver* obs,
-                                              const BeginFrameAck& ack) {}
-
 bool ExternalBeginFrameSource::IsThrottled() const {
   return true;
 }
 
 void ExternalBeginFrameSource::OnSetBeginFrameSourcePaused(bool paused) {
   if (paused_ == paused)
     return;
   paused_ = paused;
   std::unordered_set<BeginFrameObserver*> observers(observers_);
   for (auto* obs : observers)
@@ skipping 12 matching lines @@
       DCHECK((args.source_id != last_args.source_id) ||
              (args.sequence_number > last_args.sequence_number))
           << "current " << args.AsValue()->ToString() << ", last "
           << last_args.AsValue()->ToString();
       obs->OnBeginFrame(args);
     }
   }
 }
 
 }  // namespace cc