ipc: Simplify the magic required to create IPC message headers.This gets rid of having to include the files in a magic place because of xcode dependency issues, and just makes it simpler to create new IPC message classes. It also gets rid of including the X_messages_internal.h file multiple times, which simplifies things and should make the build a little faster.

In a future change, I will remove the "internal.h" files since they're no longer needed.
Review URL: http://codereview.chromium.org/5526008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@68664 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 255 insertions, 281 deletions

diff --git a/chrome/common/gpu_messages_internal.h b/chrome/common/gpu_messages_internal.h
index e4badaa..57a8917 100644
--- a/chrome/common/gpu_messages_internal.h
+++ b/chrome/common/gpu_messages_internal.h
@@ -2,13 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// This header is meant to be included in multiple passes, hence no traditional
-// header guard. It is included by backing_store_messages_internal.h
-// See ipc_message_macros.h for explanation of the macros and passes.
-
-// This file needs to be included again, even though we're actually included
-// from it via utility_messages.h.
-
 #include <vector>
 #include <string>
 
@@ -16,6 +9,8 @@
 #include "chrome/common/gpu_video_common.h"
 #include "ipc/ipc_message_macros.h"
 
+#define IPC_MESSAGE_START GpuMsgStart
+
 namespace gfx {
 class Size;
 }
@@ -30,322 +25,301 @@ class GPUInfo;
 //------------------------------------------------------------------------------
 // GPU Messages
 // These are messages from the browser to the GPU process.
-IPC_BEGIN_MESSAGES(Gpu)
-
-  // Tells the GPU process to create a new channel for communication with a
-  // given renderer.  The channel name is returned in a
-  // GpuHostMsg_ChannelEstablished message.  The renderer ID is passed so that
-  // the GPU process reuses an existing channel to that process if it exists.
-  // This ID is a unique opaque identifier generated by the browser process.
-  IPC_MESSAGE_CONTROL1(GpuMsg_EstablishChannel,
-                       int /* renderer_id */)
-
-  // Provides a synchronization point to guarantee that the processing of
-  // previous asynchronous messages (i.e., GpuMsg_EstablishChannel) has
-  // completed. (This message can't be synchronous because the
-  // GpuProcessHost uses an IPC::ChannelProxy, which sends all messages
-  // asynchronously.) Results in a GpuHostMsg_SynchronizeReply.
-  IPC_MESSAGE_CONTROL0(GpuMsg_Synchronize)
-
-  // Tells the GPU process to create a context for collecting graphics card
-  // information.
-  IPC_MESSAGE_CONTROL0(GpuMsg_CollectGraphicsInfo)
+// Tells the GPU process to create a new channel for communication with a
+// given renderer.  The channel name is returned in a
+// GpuHostMsg_ChannelEstablished message.  The renderer ID is passed so that
+// the GPU process reuses an existing channel to that process if it exists.
+// This ID is a unique opaque identifier generated by the browser process.
+IPC_MESSAGE_CONTROL1(GpuMsg_EstablishChannel,
+                     int /* renderer_id */)
+
+// Provides a synchronization point to guarantee that the processing of
+// previous asynchronous messages (i.e., GpuMsg_EstablishChannel) has
+// completed. (This message can't be synchronous because the
+// GpuProcessHost uses an IPC::ChannelProxy, which sends all messages
+// asynchronously.) Results in a GpuHostMsg_SynchronizeReply.
+IPC_MESSAGE_CONTROL0(GpuMsg_Synchronize)
+
+// Tells the GPU process to create a context for collecting graphics card
+// information.
+IPC_MESSAGE_CONTROL0(GpuMsg_CollectGraphicsInfo)
 
 #if defined(OS_MACOSX)
-  // Tells the GPU process that the browser process handled the swap
-  // buffers request with the given number. Note that it is possible
-  // for the browser process to coalesce frames; it is not guaranteed
-  // that every GpuHostMsg_AcceleratedSurfaceBuffersSwapped message
-  // will result in a buffer swap on the browser side.
-  IPC_MESSAGE_CONTROL3(GpuMsg_AcceleratedSurfaceBuffersSwappedACK,
-                       int /* renderer_id */,
-                       int32 /* route_id */,
-                       uint64 /* swap_buffers_count */)
+// Tells the GPU process that the browser process handled the swap
+// buffers request with the given number. Note that it is possible
+// for the browser process to coalesce frames; it is not guaranteed
+// that every GpuHostMsg_AcceleratedSurfaceBuffersSwapped message
+// will result in a buffer swap on the browser side.
+IPC_MESSAGE_CONTROL3(GpuMsg_AcceleratedSurfaceBuffersSwappedACK,
+                     int /* renderer_id */,
+                     int32 /* route_id */,
+                     uint64 /* swap_buffers_count */)
 #endif
 
-  // Tells the GPU process to crash.
-  IPC_MESSAGE_CONTROL0(GpuMsg_Crash)
-
-  // Tells the GPU process to hang.
-  IPC_MESSAGE_CONTROL0(GpuMsg_Hang)
+// Tells the GPU process to crash.
+IPC_MESSAGE_CONTROL0(GpuMsg_Crash)
 
-IPC_END_MESSAGES(Gpu)
+// Tells the GPU process to hang.
+IPC_MESSAGE_CONTROL0(GpuMsg_Hang)
 
 //------------------------------------------------------------------------------
 // GPU Host Messages
 // These are messages from the GPU process to the browser.
-IPC_BEGIN_MESSAGES(GpuHost)
+// Response to a GpuHostMsg_EstablishChannel message.
+IPC_MESSAGE_CONTROL2(GpuHostMsg_ChannelEstablished,
+                     IPC::ChannelHandle, /* channel_handle */
+                     GPUInfo /* GPU logging stats */)
 
-  // Response to a GpuHostMsg_EstablishChannel message.
-  IPC_MESSAGE_CONTROL2(GpuHostMsg_ChannelEstablished,
-                       IPC::ChannelHandle, /* channel_handle */
-                       GPUInfo /* GPU logging stats */)
+// Response to a GpuMsg_Synchronize message.
+IPC_MESSAGE_CONTROL0(GpuHostMsg_SynchronizeReply)
 
-  // Response to a GpuMsg_Synchronize message.
-  IPC_MESSAGE_CONTROL0(GpuHostMsg_SynchronizeReply)
-
-  // Response to a GpuMsg_CollectGraphicsInfo.
-  IPC_MESSAGE_CONTROL1(GpuHostMsg_GraphicsInfoCollected,
-                       GPUInfo /* GPU logging stats */)
+// Response to a GpuMsg_CollectGraphicsInfo.
+IPC_MESSAGE_CONTROL1(GpuHostMsg_GraphicsInfoCollected,
+                     GPUInfo /* GPU logging stats */)
 
 #if defined(OS_LINUX)
-  // Get the XID for a view ID.
-  IPC_SYNC_MESSAGE_CONTROL1_1(GpuHostMsg_GetViewXID,
-                              gfx::NativeViewId, /* view */
-                              unsigned long /* xid */)
+// Get the XID for a view ID.
+IPC_SYNC_MESSAGE_CONTROL1_1(GpuHostMsg_GetViewXID,
+                            gfx::NativeViewId, /* view */
+                            unsigned long /* xid */)
 
-  // Release the lock on the window.
-  // If the associated view has been destroyed, destroy the window.
-  IPC_MESSAGE_CONTROL1(GpuHostMsg_ReleaseXID,
-                       unsigned long /* xid */)
+// Release the lock on the window.
+// If the associated view has been destroyed, destroy the window.
+IPC_MESSAGE_CONTROL1(GpuHostMsg_ReleaseXID,
+                     unsigned long /* xid */)
 
-  IPC_SYNC_MESSAGE_CONTROL2_1(GpuHostMsg_ResizeXID,
-                              unsigned long, /* xid */
-                              gfx::Size, /* size */
-                              bool /* success */)
+IPC_SYNC_MESSAGE_CONTROL2_1(GpuHostMsg_ResizeXID,
+                            unsigned long, /* xid */
+                            gfx::Size, /* size */
+                            bool /* success */)
 
 #elif defined(OS_MACOSX)
-  // This message, used on Mac OS X 10.6 and later (where IOSurface is
-  // supported), is sent from the GPU process to the browser to indicate that a
-  // new backing store was allocated for the given "window" (fake
-  // PluginWindowHandle). The renderer ID and render view ID are needed in
-  // order to uniquely identify the RenderWidgetHostView on the browser side.
-  IPC_MESSAGE_CONTROL1(GpuHostMsg_AcceleratedSurfaceSetIOSurface,
-                       GpuHostMsg_AcceleratedSurfaceSetIOSurface_Params)
-
-  // This message notifies the browser process that the renderer
-  // swapped the buffers associated with the given "window", which
-  // should cause the browser to redraw the compositor's contents.
-  IPC_MESSAGE_CONTROL1(GpuHostMsg_AcceleratedSurfaceBuffersSwapped,
-                       GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params)
+// This message, used on Mac OS X 10.6 and later (where IOSurface is
+// supported), is sent from the GPU process to the browser to indicate that a
+// new backing store was allocated for the given "window" (fake
+// PluginWindowHandle). The renderer ID and render view ID are needed in
+// order to uniquely identify the RenderWidgetHostView on the browser side.
+IPC_MESSAGE_CONTROL1(GpuHostMsg_AcceleratedSurfaceSetIOSurface,
+                     GpuHostMsg_AcceleratedSurfaceSetIOSurface_Params)
+
+// This message notifies the browser process that the renderer
+// swapped the buffers associated with the given "window", which
+// should cause the browser to redraw the compositor's contents.
+IPC_MESSAGE_CONTROL1(GpuHostMsg_AcceleratedSurfaceBuffersSwapped,
+                     GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params)
 #elif defined(OS_WIN)
-  // Get the HWND for the compositor window and if necessary, create it
-  IPC_SYNC_MESSAGE_CONTROL2_1(GpuHostMsg_GetCompositorHostWindow,
-                              int32, /* renderer_id */
-                              int32, /* render_view_id */
-                              gfx::PluginWindowHandle /* compositor_host_id */)
-
-  IPC_MESSAGE_CONTROL2(GpuHostMsg_ScheduleComposite,
-                       int32, /* renderer_id */
-                       int32 /* render_view_id */)
+// Get the HWND for the compositor window and if necessary, create it
+IPC_SYNC_MESSAGE_CONTROL2_1(GpuHostMsg_GetCompositorHostWindow,
+                            int32, /* renderer_id */
+                            int32, /* render_view_id */
+                            gfx::PluginWindowHandle /* compositor_host_id */)
+
+IPC_MESSAGE_CONTROL2(GpuHostMsg_ScheduleComposite,
+                     int32, /* renderer_id */
+                     int32 /* render_view_id */)
 #endif
 
-IPC_END_MESSAGES(GpuHost)
-
 //------------------------------------------------------------------------------
 // GPU Channel Messages
 // These are messages from a renderer process to the GPU process.
-IPC_BEGIN_MESSAGES(GpuChannel)
-
-  // Tells the GPU process to create a new command buffer that renders directly
-  // to a native view. The |render_view_id| is currently needed only on Mac OS
-  // X in order to identify the window on the browser side into which the
-  // rendering results go. A corresponding GpuCommandBufferStub is created.
-  IPC_SYNC_MESSAGE_CONTROL3_1(GpuChannelMsg_CreateViewCommandBuffer,
-                              gfx::NativeViewId, /* view */
-                              int32, /* render_view_id */
-                              GPUCreateCommandBufferConfig, /* init_params */
-                              int32 /* route_id */)
-
-  // Tells the GPU process to create a new command buffer that renders to an
-  // offscreen frame buffer. If parent_route_id is not zero, the texture backing
-  // the frame buffer is mapped into the corresponding parent command buffer's
-  // namespace, with the name of parent_texture_id. This ID is in the parent's
-  // namespace.
-  IPC_SYNC_MESSAGE_CONTROL4_1(GpuChannelMsg_CreateOffscreenCommandBuffer,
-                              int32, /* parent_route_id */
-                              gfx::Size, /* size */
-                              GPUCreateCommandBufferConfig, /* init_params */
-                              uint32, /* parent_texture_id */
-                              int32 /* route_id */)
-
-  // The CommandBufferProxy sends this to the GpuCommandBufferStub in its
-  // destructor, so that the stub deletes the actual CommandBufferService
-  // object that it's hosting.
-  // TODO(apatrick): Implement this.
-  IPC_SYNC_MESSAGE_CONTROL1_0(GpuChannelMsg_DestroyCommandBuffer,
-                              int32 /* instance_id */)
-
-  // Create hardware video decoder && associate it with the output |decoder_id|;
-  // We need this to be control message because we had to map the GpuChannel and
-  // |decoder_id|.
-  IPC_MESSAGE_CONTROL2(GpuChannelMsg_CreateVideoDecoder,
-                       int32, /* context_route_id */
-                       int32) /* decoder_id */
-
-  // Release all resource of the hardware video decoder which was assocaited
-  // with the input |decoder_id|.
-  // TODO(hclam): This message needs to be asynchronous.
-  IPC_SYNC_MESSAGE_CONTROL1_0(GpuChannelMsg_DestroyVideoDecoder,
-                              int32 /* decoder_id */)
-
-IPC_END_MESSAGES(GpuChannel)
+// Tells the GPU process to create a new command buffer that renders directly
+// to a native view. The |render_view_id| is currently needed only on Mac OS
+// X in order to identify the window on the browser side into which the
+// rendering results go. A corresponding GpuCommandBufferStub is created.
+IPC_SYNC_MESSAGE_CONTROL3_1(GpuChannelMsg_CreateViewCommandBuffer,
+                            gfx::NativeViewId, /* view */
+                            int32, /* render_view_id */
+                            GPUCreateCommandBufferConfig, /* init_params */
+                            int32 /* route_id */)
+
+// Tells the GPU process to create a new command buffer that renders to an
+// offscreen frame buffer. If parent_route_id is not zero, the texture backing
+// the frame buffer is mapped into the corresponding parent command buffer's
+// namespace, with the name of parent_texture_id. This ID is in the parent's
+// namespace.
+IPC_SYNC_MESSAGE_CONTROL4_1(GpuChannelMsg_CreateOffscreenCommandBuffer,
+                            int32, /* parent_route_id */
+                            gfx::Size, /* size */
+                            GPUCreateCommandBufferConfig, /* init_params */
+                            uint32, /* parent_texture_id */
+                            int32 /* route_id */)
+
+// The CommandBufferProxy sends this to the GpuCommandBufferStub in its
+// destructor, so that the stub deletes the actual CommandBufferService
+// object that it's hosting.
+// TODO(apatrick): Implement this.
+IPC_SYNC_MESSAGE_CONTROL1_0(GpuChannelMsg_DestroyCommandBuffer,
+                            int32 /* instance_id */)
+
+// Create hardware video decoder && associate it with the output |decoder_id|;
+// We need this to be control message because we had to map the GpuChannel and
+// |decoder_id|.
+IPC_MESSAGE_CONTROL2(GpuChannelMsg_CreateVideoDecoder,
+                     int32, /* context_route_id */
+                     int32) /* decoder_id */
+
+// Release all resource of the hardware video decoder which was assocaited
+// with the input |decoder_id|.
+// TODO(hclam): This message needs to be asynchronous.
+IPC_SYNC_MESSAGE_CONTROL1_0(GpuChannelMsg_DestroyVideoDecoder,
+                            int32 /* decoder_id */)
 
 //------------------------------------------------------------------------------
 // GPU Command Buffer Messages
 // These are messages between a renderer process to the GPU process relating to
 // a single OpenGL context.
-IPC_BEGIN_MESSAGES(GpuCommandBuffer)
-  // Initialize a command buffer with the given number of command entries.
-  // Returns the shared memory handle for the command buffer mapped to the
-  // calling process.
-  IPC_SYNC_MESSAGE_ROUTED1_1(GpuCommandBufferMsg_Initialize,
-                             int32 /* size */,
-                             base::SharedMemoryHandle /* ring_buffer */)
-
-  // Get the current state of the command buffer.
-  IPC_SYNC_MESSAGE_ROUTED0_1(GpuCommandBufferMsg_GetState,
-                             gpu::CommandBuffer::State /* state */)
-
-  // Get the current state of the command buffer asynchronously. State is
-  // returned via UpdateState message.
-  IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_AsyncGetState)
-
-  // Synchronize the put and get offsets of both processes. Caller passes its
-  // current put offset. Current state (including get offset) is returned.
-  IPC_SYNC_MESSAGE_ROUTED1_1(GpuCommandBufferMsg_Flush,
-                             int32 /* put_offset */,
-                             gpu::CommandBuffer::State /* state */)
-
-  // Asynchronously synchronize the put and get offsets of both processes.
-  // Caller passes its current put offset. Current state (including get offset)
-  // is returned via an UpdateState message.
-  IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_AsyncFlush,
-                      int32 /* put_offset */)
-
-  // Return the current state of the command buffer following a request via
-  // an AsyncGetState or AsyncFlush message. (This message is sent from the
-  // GPU process to the renderer process.)
-  IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_UpdateState,
-                      gpu::CommandBuffer::State /* state */)
-
-  // Indicates that a SwapBuffers call has been issued.
-  IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_SwapBuffers)
-
-  // Create a shared memory transfer buffer. Returns an id that can be used to
-  // identify the transfer buffer from a comment.
-  IPC_SYNC_MESSAGE_ROUTED1_1(GpuCommandBufferMsg_CreateTransferBuffer,
-                             int32 /* size */,
-                             int32 /* id */)
-
-  // Destroy a previously created transfer buffer.
-  IPC_SYNC_MESSAGE_ROUTED1_0(GpuCommandBufferMsg_DestroyTransferBuffer,
-                             int32 /* id */)
-
-  // Get the shared memory handle for a transfer buffer mapped to the callers
-  // process.
-  IPC_SYNC_MESSAGE_ROUTED1_2(GpuCommandBufferMsg_GetTransferBuffer,
-                             int32 /* id */,
-                             base::SharedMemoryHandle /* transfer_buffer */,
-                             uint32 /* size */)
-
-  // Send from command buffer stub to proxy when window is invalid and must be
-  // repainted.
-  IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_NotifyRepaint)
-
-  // Tells the GPU process to resize an offscreen frame buffer.
-  IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_ResizeOffscreenFrameBuffer,
-                      gfx::Size /* size */)
+// Initialize a command buffer with the given number of command entries.
+// Returns the shared memory handle for the command buffer mapped to the
+// calling process.
+IPC_SYNC_MESSAGE_ROUTED1_1(GpuCommandBufferMsg_Initialize,
+                           int32 /* size */,
+                           base::SharedMemoryHandle /* ring_buffer */)
+
+// Get the current state of the command buffer.
+IPC_SYNC_MESSAGE_ROUTED0_1(GpuCommandBufferMsg_GetState,
+                           gpu::CommandBuffer::State /* state */)
+
+// Get the current state of the command buffer asynchronously. State is
+// returned via UpdateState message.
+IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_AsyncGetState)
+
+// Synchronize the put and get offsets of both processes. Caller passes its
+// current put offset. Current state (including get offset) is returned.
+IPC_SYNC_MESSAGE_ROUTED1_1(GpuCommandBufferMsg_Flush,
+                           int32 /* put_offset */,
+                           gpu::CommandBuffer::State /* state */)
+
+// Asynchronously synchronize the put and get offsets of both processes.
+// Caller passes its current put offset. Current state (including get offset)
+// is returned via an UpdateState message.
+IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_AsyncFlush,
+                    int32 /* put_offset */)
+
+// Return the current state of the command buffer following a request via
+// an AsyncGetState or AsyncFlush message. (This message is sent from the
+// GPU process to the renderer process.)
+IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_UpdateState,
+                    gpu::CommandBuffer::State /* state */)
+
+// Indicates that a SwapBuffers call has been issued.
+IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_SwapBuffers)
+
+// Create a shared memory transfer buffer. Returns an id that can be used to
+// identify the transfer buffer from a comment.
+IPC_SYNC_MESSAGE_ROUTED1_1(GpuCommandBufferMsg_CreateTransferBuffer,
+                           int32 /* size */,
+                           int32 /* id */)
+
+// Destroy a previously created transfer buffer.
+IPC_SYNC_MESSAGE_ROUTED1_0(GpuCommandBufferMsg_DestroyTransferBuffer,
+                           int32 /* id */)
+
+// Get the shared memory handle for a transfer buffer mapped to the callers
+// process.
+IPC_SYNC_MESSAGE_ROUTED1_2(GpuCommandBufferMsg_GetTransferBuffer,
+                           int32 /* id */,
+                           base::SharedMemoryHandle /* transfer_buffer */,
+                           uint32 /* size */)
+
+// Send from command buffer stub to proxy when window is invalid and must be
+// repainted.
+IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_NotifyRepaint)
+
+// Tells the GPU process to resize an offscreen frame buffer.
+IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_ResizeOffscreenFrameBuffer,
+                    gfx::Size /* size */)
 
 #if defined(OS_MACOSX)
-  // On Mac OS X the GPU plugin must be offscreen, because there is no
-  // true cross-process window hierarchy. For this reason we must send
-  // resize events explicitly to the command buffer stub so it can
-  // reallocate its backing store and send the new one back to the
-  // browser. This message is currently used only on 10.6 and later.
-  IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_SetWindowSize,
-                      gfx::Size /* size */)
+// On Mac OS X the GPU plugin must be offscreen, because there is no
+// true cross-process window hierarchy. For this reason we must send
+// resize events explicitly to the command buffer stub so it can
+// reallocate its backing store and send the new one back to the
+// browser. This message is currently used only on 10.6 and later.
+IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_SetWindowSize,
+                    gfx::Size /* size */)
 #endif
 
-IPC_END_MESSAGES(GpuCommandBuffer)
-
 //------------------------------------------------------------------------------
 // GPU Video Decoder Messages
 // These messages are sent from Renderer process to GPU process.
-IPC_BEGIN_MESSAGES(GpuVideoDecoder)
-  // Initialize and configure GpuVideoDecoder asynchronously.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderMsg_Initialize,
-                      GpuVideoDecoderInitParam)
-
-  // Destroy and release GpuVideoDecoder asynchronously.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderMsg_Destroy)
+// Initialize and configure GpuVideoDecoder asynchronously.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderMsg_Initialize,
+                    GpuVideoDecoderInitParam)
 
-  // Start decoder flushing operation.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderMsg_Flush)
+// Destroy and release GpuVideoDecoder asynchronously.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderMsg_Destroy)
 
-  // Tell the decoder to start prerolling.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderMsg_Preroll)
+// Start decoder flushing operation.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderMsg_Flush)
 
-  // Send input buffer to GpuVideoDecoder.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderMsg_EmptyThisBuffer,
-                      GpuVideoDecoderInputBufferParam)
+// Tell the decoder to start prerolling.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderMsg_Preroll)
 
-  // Ask the GPU process to produce a video frame with the ID.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderMsg_ProduceVideoFrame,
-                      int32) /* Video Frame ID */
+// Send input buffer to GpuVideoDecoder.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderMsg_EmptyThisBuffer,
+                    GpuVideoDecoderInputBufferParam)
 
-  // Sent from Renderer process to the GPU process to notify that textures are
-  // generated for a video frame.
-  IPC_MESSAGE_ROUTED2(GpuVideoDecoderMsg_VideoFrameAllocated,
-                      int32, /* Video Frame ID */
-                      std::vector<uint32>) /* Textures for video frame */
+// Ask the GPU process to produce a video frame with the ID.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderMsg_ProduceVideoFrame,
+                    int32) /* Video Frame ID */
 
-IPC_END_MESSAGES(GpuVideoDecoder)
+// Sent from Renderer process to the GPU process to notify that textures are
+// generated for a video frame.
+IPC_MESSAGE_ROUTED2(GpuVideoDecoderMsg_VideoFrameAllocated,
+                    int32, /* Video Frame ID */
+                    std::vector<uint32>) /* Textures for video frame */
 
 //------------------------------------------------------------------------------
 // GPU Video Decoder Host Messages
 // These messages are sent from GPU process to Renderer process.
-IPC_BEGIN_MESSAGES(GpuVideoDecoderHost)
-  // Inform GpuVideoDecoderHost that a GpuVideoDecoder is created.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_CreateVideoDecoderDone,
-                      int32) /* decoder_id */
-
-  // Confirm GpuVideoDecoder had been initialized or failed to initialize.
-  // TODO(hclam): Change this to Done instead of ACK.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_InitializeACK,
-                      GpuVideoDecoderInitDoneParam)
-
-  // Confrim GpuVideoDecoder had been destroyed properly.
-  // TODO(hclam): Change this to Done instead of ACK.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_DestroyACK)
-
-  // Confirm decoder had been flushed.
-  // TODO(hclam): Change this to Done instead of ACK.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_FlushACK)
-
-  // Confirm preroll operation is done.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_PrerollDone)
-
-  // GpuVideoDecoder has consumed input buffer from transfer buffer.
-  // TODO(hclam): Change this to Done instead of ACK.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_EmptyThisBufferACK)
-
-  // GpuVideoDecoder require new input buffer.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_EmptyThisBufferDone)
-
-  // GpuVideoDecoder reports that a video frame is ready to be consumed.
-  IPC_MESSAGE_ROUTED4(GpuVideoDecoderHostMsg_ConsumeVideoFrame,
-                      int32, /* Video Frame ID */
-                      int64, /* Timestamp in microseconds */
-                      int64, /* Duration in microseconds */
-                      int32) /* Flags */
-
-  // Allocate video frames for output of the hardware video decoder.
-  IPC_MESSAGE_ROUTED4(GpuVideoDecoderHostMsg_AllocateVideoFrames,
-                      int32,  /* Number of video frames to generate */
-                      uint32, /* Width of the video frame */
-                      uint32, /* Height of the video frame */
-                      int32   /* Format of the video frame */)
-
-  // Release all video frames allocated for a hardware video decoder.
-  IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_ReleaseAllVideoFrames)
-
-  // GpuVideoDecoder report output format change.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_MediaFormatChange,
-                      GpuVideoDecoderFormatChangeParam)
-
-  // GpuVideoDecoder report error.
-  IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_ErrorNotification,
-                      GpuVideoDecoderErrorInfoParam)
-
-IPC_END_MESSAGES(GpuVideoDecoderHost)
+// Inform GpuVideoDecoderHost that a GpuVideoDecoder is created.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_CreateVideoDecoderDone,
+                    int32) /* decoder_id */
+
+// Confirm GpuVideoDecoder had been initialized or failed to initialize.
+// TODO(hclam): Change this to Done instead of ACK.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_InitializeACK,
+                    GpuVideoDecoderInitDoneParam)
+
+// Confrim GpuVideoDecoder had been destroyed properly.
+// TODO(hclam): Change this to Done instead of ACK.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_DestroyACK)
+
+// Confirm decoder had been flushed.
+// TODO(hclam): Change this to Done instead of ACK.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_FlushACK)
+
+// Confirm preroll operation is done.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_PrerollDone)
+
+// GpuVideoDecoder has consumed input buffer from transfer buffer.
+// TODO(hclam): Change this to Done instead of ACK.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_EmptyThisBufferACK)
+
+// GpuVideoDecoder require new input buffer.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_EmptyThisBufferDone)
+
+// GpuVideoDecoder reports that a video frame is ready to be consumed.
+IPC_MESSAGE_ROUTED4(GpuVideoDecoderHostMsg_ConsumeVideoFrame,
+                    int32, /* Video Frame ID */
+                    int64, /* Timestamp in microseconds */
+                    int64, /* Duration in microseconds */
+                    int32) /* Flags */
+
+// Allocate video frames for output of the hardware video decoder.
+IPC_MESSAGE_ROUTED4(GpuVideoDecoderHostMsg_AllocateVideoFrames,
+                    int32,  /* Number of video frames to generate */
+                    uint32, /* Width of the video frame */
+                    uint32, /* Height of the video frame */
+                    int32   /* Format of the video frame */)
+
+// Release all video frames allocated for a hardware video decoder.
+IPC_MESSAGE_ROUTED0(GpuVideoDecoderHostMsg_ReleaseAllVideoFrames)
+
+// GpuVideoDecoder report output format change.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_MediaFormatChange,
+                    GpuVideoDecoderFormatChangeParam)
+
+// GpuVideoDecoder report error.
+IPC_MESSAGE_ROUTED1(GpuVideoDecoderHostMsg_ErrorNotification,
+                    GpuVideoDecoderErrorInfoParam)