cc: Delete channel abstraction between proxies.

cc/trees/channel_impl.h

-// 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.
-
-#ifndef CC_TREES_CHANNEL_IMPL_H_
-#define CC_TREES_CHANNEL_IMPL_H_
-
-#include "cc/base/cc_export.h"
-#include "cc/trees/proxy_common.h"
-
-namespace cc {
-
-class MutatorEvents;
-
-// Channel used to send commands to and receive commands from ProxyMain.
-// The ChannelImpl implementation creates and owns ProxyImpl on receiving the
-// InitializeImpl call from ChannelMain.
-// See channel_main.h
-class CC_EXPORT ChannelImpl {
- public:
-  // Interface for commands sent to ProxyMain
-  virtual void DidReceiveCompositorFrameAck() = 0;
-  virtual void BeginMainFrameNotExpectedSoon() = 0;
-  virtual void DidCommitAndDrawFrame() = 0;
-  virtual void SetAnimationEvents(std::unique_ptr<MutatorEvents> queue) = 0;
-  virtual void DidLoseCompositorFrameSink() = 0;
-  virtual void RequestNewCompositorFrameSink() = 0;
-  virtual void DidInitializeCompositorFrameSink(bool success) = 0;
-  virtual void DidCompletePageScaleAnimation() = 0;
-  virtual void BeginMainFrame(
-      std::unique_ptr<BeginMainFrameAndCommitState> begin_main_frame_state) = 0;
-
- protected:
-  virtual ~ChannelImpl() {}
-};
-
-}  // namespace cc
-
-#endif  // CC_TREES_CHANNEL_IMPL_H_