Route IPC through browser when creating a viewable command buffer.

The communications path for creating a viewable command buffer used to be directly from the renderer (gpu_channel.cc) to the gpu process (gpu_channel.cc).  This patch makes the browser an intermediary:

- renderer (gpu_channel.cc) makes a synchronous request to the browser (picked up in renderer_message_filter.cc and forwarded to gpu_process_host.cc)

- browser (gpu_process_host.cc) makes an asynchronous request to the gpu process (picked up in gpu_thread.cc and forwarded to gpu_channel.cc) for the command buffer

- gpu process (gpu_thread.cc) sends an ACK with the route_id for the command buffer back to the browser (gpu_process_host.cc)

- browser (gpu_process_host.cc) sends a delayed reply back to the renderer
(gpu_channel_host.cc), which had blocked

There are several motivations for this patch:

- creating an onscreen command buffer requires a window to draw into (which is acquired/locked in the browser); by routing through the browser, we can acquire the get the window beforehand (thereby preventing a deadlock in some other work that I'm doing)

- we can eliminate several separate synchronous IPC messages for obtaining and releasing the window associated with drawing (I've tried to unify the different code paths for Linux, Windows, and Mac)

- in the future, we can have the browser allocate SHM for the command buffer and transfer buffers, allowing us to sandbox the gpu process

BUG=none
TEST=by hand on all 3 platforms, trybots

Review URL: http://codereview.chromium.org/6343006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72798 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 5 deletions

diff --git a/chrome/renderer/gpu_channel_host.cc b/chrome/renderer/gpu_channel_host.cc
index 719e8bf..10b52ed 100644
--- a/chrome/renderer/gpu_channel_host.cc
+++ b/chrome/renderer/gpu_channel_host.cc
@@ -7,8 +7,10 @@
 #include "chrome/common/child_process.h"
 #include "chrome/common/gpu_create_command_buffer_config.h"
 #include "chrome/common/gpu_messages.h"
+#include "chrome/common/render_messages.h"
 #include "chrome/renderer/command_buffer_proxy.h"
 #include "chrome/renderer/gpu_video_service_host.h"
+#include "chrome/renderer/render_thread.h"
 
 GpuChannelHost::GpuChannelHost() : state_(kUnconnected) {
 }
@@ -90,7 +92,6 @@ bool GpuChannelHost::Send(IPC::Message* message) {
 }
 
 CommandBufferProxy* GpuChannelHost::CreateViewCommandBuffer(
-    gfx::NativeViewId view,
     int render_view_id,
     const std::string& allowed_extensions,
     const std::vector<int32>& attribs) {
@@ -101,10 +102,8 @@ CommandBufferProxy* GpuChannelHost::CreateViewCommandBuffer(
 
   GPUCreateCommandBufferConfig init_params(allowed_extensions, attribs);
   int32 route_id;
-  if (!Send(new GpuChannelMsg_CreateViewCommandBuffer(view,
-                                                      render_view_id,
-                                                      init_params,
-                                                      &route_id))) {
+  if (!RenderThread::current()->Send(new ViewHostMsg_CreateViewCommandBuffer(
+       render_view_id, init_params, &route_id))) {
     return NULL;
   }