Clean up Mac swap acknowledgement code

content/common/gpu/gpu_messages.h

 // Copyright (c) 2012 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.
 
 // Multiply-included message file, hence no include guard here, but see below
 // for a much smaller-than-usual include guard section.
 
 #include <string>
 #include <vector>
 
@@ skipping 103 matching lines @@
   IPC_STRUCT_MEMBER(gfx::BufferFormat, format)
   IPC_STRUCT_MEMBER(int32, client_id)
 IPC_STRUCT_END()
 
 #if defined(OS_MACOSX)
 IPC_STRUCT_BEGIN(GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params)
   IPC_STRUCT_MEMBER(int32, surface_id)
   IPC_STRUCT_MEMBER(uint64, surface_handle)
   IPC_STRUCT_MEMBER(int32, route_id)
   IPC_STRUCT_MEMBER(gfx::Size, size)
-  IPC_STRUCT_MEMBER(gfx::Rect, damage_rect)
   IPC_STRUCT_MEMBER(float, scale_factor)
   IPC_STRUCT_MEMBER(std::vector<ui::LatencyInfo>, latency_info)
 IPC_STRUCT_END()
 
 IPC_STRUCT_BEGIN(AcceleratedSurfaceMsg_BufferPresented_Params)
-  // If the browser needs framerate throttling based on GPU back-pressure to be
-  // disabled (e.g, because the NSView isn't visible but tab capture is active),
-  // then this is set to true.
-  IPC_STRUCT_MEMBER(bool, disable_throttling)
-  // If the browser is drawing to the screen, this is the CGL renderer ID of
-  // the GL context that the brower is using.
-  IPC_STRUCT_MEMBER(int32, renderer_id)
   // The vsync parameters, to synchronize presentation with the display.
   IPC_STRUCT_MEMBER(base::TimeTicks, vsync_timebase)
   IPC_STRUCT_MEMBER(base::TimeDelta, vsync_interval)
 IPC_STRUCT_END()
 #endif
 
 IPC_STRUCT_BEGIN(AcceleratedJpegDecoderMsg_Decode_Params)
   IPC_STRUCT_MEMBER(int32, input_buffer_id)
   IPC_STRUCT_MEMBER(gfx::Size, coded_size)
   IPC_STRUCT_MEMBER(base::SharedMemoryHandle, input_buffer_handle)
@@ skipping 665 matching lines @@
 IPC_MESSAGE_ROUTED0(AcceleratedJpegDecoderMsg_Destroy)
 
 //------------------------------------------------------------------------------
 // Accelerated JPEG Decoder Host Messages
 // These messages are sent from the GPU process to Browser process.
 //
 // Report decode status.
 IPC_MESSAGE_ROUTED2(AcceleratedJpegDecoderHostMsg_DecodeAck,
                     int32, /* bitstream_buffer_id */
                     media::JpegDecodeAccelerator::Error /* error */)