Added GPU process "echo" IPC message.

content/common/gpu/gpu_command_buffer_stub.cc

 // Copyright (c) 2011 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.
 
 #if defined(ENABLE_GPU)
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/process_util.h"
 #include "base/shared_memory.h"
@@ skipping 179 matching lines @@
         requested_attribs_,
         channel_->share_group())) {
 #endif
       command_buffer_->SetPutOffsetChangeCallback(
           NewCallback(scheduler_.get(),
                       &gpu::GpuScheduler::PutChanged));
       command_buffer_->SetParseErrorCallback(
           NewCallback(this, &GpuCommandBufferStub::OnParseError));
       scheduler_->SetScheduledCallback(
           NewCallback(channel_, &GpuChannel::OnScheduled));
+
+#if defined(OS_MACOSX)
       scheduler_->SetSwapBuffersCallback(
           NewCallback(this, &GpuCommandBufferStub::OnSwapBuffers));
+#endif
+
       // On TOUCH_UI, the ImageTransportSurface handles co-ordinating the
       // resize with the browser process. The ImageTransportSurface sets it's
       // own resize callback, so we shouldn't do it here.
 #if !defined(TOUCH_UI)
       if (handle_ != gfx::kNullPluginWindow) {
         scheduler_->SetResizeCallback(
             NewCallback(this, &GpuCommandBufferStub::OnResize));
       }
 #endif
       if (watchdog_)
@@ skipping 188 matching lines @@
                                          &transfer_buffer);
     size = buffer.size;
   }
 
   GpuCommandBufferMsg_GetTransferBuffer::WriteReplyParams(reply_message,
                                                           transfer_buffer,
                                                           size);
   Send(reply_message);
 }
 
+#if defined(OS_MACOSX)
 void GpuCommandBufferStub::OnSwapBuffers() {
   TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnSwapBuffers");
-  ReportState();
-
-#if defined(OS_MACOSX)
   if (handle_) {
     // To swap on OSX, we have to send a message to the browser to get the
     // context put onscreen.
     GpuChannelManager* gpu_channel_manager = channel_->gpu_channel_manager();
     GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
     params.renderer_id = renderer_id_;
     params.render_view_id = render_view_id_;
     params.window = handle_;
     params.surface_id = scheduler_->GetSurfaceId();
     params.route_id = route_id();
     params.swap_buffers_count = scheduler_->swap_buffers_count();
     gpu_channel_manager->Send(
         new GpuHostMsg_AcceleratedSurfaceBuffersSwapped(params));
     scheduler_->SetScheduled(false);
   }
-#else
-  // Notify the upstream commandbuffer that the swapbuffers has completed.
-  Send(new GpuCommandBufferMsg_SwapBuffers(route_id_));
+}
 #endif
-}
 
 void GpuCommandBufferStub::OnCommandProcessed() {
   if (watchdog_)
     watchdog_->CheckArmed();
 }
 
 #if defined(OS_MACOSX)
 void GpuCommandBufferStub::AcceleratedSurfaceBuffersSwapped(
     uint64 swap_buffers_count) {
   TRACE_EVENT1("gpu",
                "GpuCommandBufferStub::AcceleratedSurfaceBuffersSwapped",
                "frame", swap_buffers_count);
   DCHECK(handle_ != gfx::kNullPluginWindow);
 
   // Multiple swapbuffers may get consolidated together into a single
   // AcceleratedSurfaceBuffersSwapped call. Upstream code listening to the
   // GpuCommandBufferMsg_SwapBuffers expects to be called one time for every
   // swap. So, send one SwapBuffers message for every outstanding swap.
   uint64 delta = swap_buffers_count -
       scheduler_->acknowledged_swap_buffers_count();
   scheduler_->set_acknowledged_swap_buffers_count(swap_buffers_count);
 
   for(uint64 i = 0; i < delta; i++) {
-    // Notify the upstream commandbuffer that the swapbuffers has completed.
-    Send(new GpuCommandBufferMsg_SwapBuffers(route_id_));
-
-    // Wake up the GpuScheduler to start doing work again.
+    // Wake up the GpuScheduler to start doing work again. When the scheduler
+    // wakes up, it will send any deferred echo acknowledgements, triggering
+    // associated swapbuffer callbacks.
     scheduler_->SetScheduled(true);
   }
 }
 #endif  // defined(OS_MACOSX)
 
 void GpuCommandBufferStub::OnResize(gfx::Size size) {
   if (handle_ == gfx::kNullPluginWindow)
     return;
 
 #if defined(OS_MACOSX)
@@ skipping 78 matching lines @@
   channel_->AddRoute(decoder_route_id, decoder);
   decoder->Initialize(configs, reply_message);
 }
 
 void GpuCommandBufferStub::OnDestroyVideoDecoder(int decoder_route_id) {
   channel_->RemoveRoute(decoder_route_id);
   video_decoders_.Remove(decoder_route_id);
 }
 
 #endif  // defined(ENABLE_GPU)