[cc] Remove remaining_frames from BeginFrameAck.

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 85 matching lines @@
   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) {
-  if (ack.remaining_frames == 0 && observers_.find(obs) != observers_.end()) {
+  if (observers_.find(obs) != observers_.end()) {
     pending_begin_frame_observers_.insert(obs);
     time_source_->SetActive(true);
   }
 }
 
 bool BackToBackBeginFrameSource::IsThrottled() const {
   return false;
 }
 
 void BackToBackBeginFrameSource::OnTimerTick() {
@@ skipping 313 matching lines @@
   if (!frame_active_ || !ack_tracker_.AllObserversFinishedFrame())
     return;
   FinishFrame();
 }
 
 void ExternalBeginFrameSource::FinishFrame() {
   frame_active_ = false;
 
   BeginFrameAck ack(missed_begin_frame_args_.source_id,
                     missed_begin_frame_args_.sequence_number,
-                    ack_tracker_.LatestConfirmedSequenceNumber(), 0,
+                    ack_tracker_.LatestConfirmedSequenceNumber(),
                     ack_tracker_.AnyObserversHadDamage());
   client_->OnDidFinishFrame(ack);
 }
 
 }  // namespace cc