Send vsync timebase updates to the browser compositor

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 359 matching lines @@
 // the given surface. The browser must send an ACK once this operation
 // is complete.
 IPC_MESSAGE_CONTROL1(GpuHostMsg_AcceleratedSurfaceRelease,
                      GpuHostMsg_AcceleratedSurfaceRelease_Params)
 
 // Tells the browser to release resources for the given surface until the next
 // time swap buffers or post sub buffer is sent.
 IPC_MESSAGE_CONTROL1(GpuHostMsg_AcceleratedSurfaceSuspend,
                      int32 /* surface_id */)
 
+// Tells the browser about updated parameters for vsync alignment.
+IPC_MESSAGE_CONTROL2(GpuHostMsg_UpdateVSyncParameters,

[piman, 2012/10/24 16:56:54]

Something is missing here, when you have multiple screens (multiple GLSurfaces,
multiple refresh rate/alignment).
You need an identifier to associate this data to the right surface.

[ajuma, 2012/10/26 20:12:39]

Done.

+                     base::TimeTicks /* timebase */,
+                     base::TimeDelta /* interval */)
+
 //------------------------------------------------------------------------------
 // GPU Channel Messages
 // These are messages from a renderer process to the GPU process.
 
 // Tells the GPU process to create a new command buffer that renders to an
 // offscreen frame buffer.
 IPC_SYNC_MESSAGE_CONTROL2_1(GpuChannelMsg_CreateOffscreenCommandBuffer,
                             gfx::Size, /* size */
                             GPUCreateCommandBufferConfig, /* init_params */
                             int32 /* route_id */)
@@ skipping 259 matching lines @@
 
 // Confirm decoder has been flushed.
 IPC_MESSAGE_ROUTED0(AcceleratedVideoDecoderHostMsg_FlushDone)
 
 // Confirm decoder has been reset.
 IPC_MESSAGE_ROUTED0(AcceleratedVideoDecoderHostMsg_ResetDone)
 
 // Video decoder has encountered an error.
 IPC_MESSAGE_ROUTED1(AcceleratedVideoDecoderHostMsg_ErrorNotification,
                     uint32) /* Error ID */