Aura: Don't create GL context for CreateSharedSurfaceHandle()

content/browser/aura/gpu_process_transport_factory.cc

Index: content/browser/aura/gpu_process_transport_factory.cc
diff --git a/content/browser/aura/gpu_process_transport_factory.cc b/content/browser/aura/gpu_process_transport_factory.cc
index b5a8e7a4f04209a2614a81907590c00306bdf5d1..59ebd9b0d40b905a533bc9bea34dc77298313ef0 100644
--- a/content/browser/aura/gpu_process_transport_factory.cc
+++ b/content/browser/aura/gpu_process_transport_factory.cc
@@ -27,6 +27,7 @@
 #include "content/common/gpu/client/gpu_channel_host.h"
 #include "content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h"
 #include "content/common/gpu/gpu_process_launch_causes.h"
+#include "content/public/browser/render_process_host.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "ui/compositor/compositor.h"
@@ -147,6 +148,13 @@ GpuProcessTransportFactory::GpuProcessTransportFactory()
     : callback_factory_(this) {
   output_surface_proxy_ = new BrowserCompositorOutputSurfaceProxy(
       &output_surface_map_);
+  if (GpuDataManagerImpl::GetInstance()->CanUseGpuBrowserCompositor()) {
+    CauseForGpuLaunch cause = CAUSE_FOR_GPU_LAUNCH_BROWSER_STARTUP;
+    BrowserGpuChannelHostFactory::instance()->EstablishGpuChannel(
+        cause,
+        base::Bind(&GpuProcessTransportFactory::OnGpuChannelReady,
+                   callback_factory_.GetWeakPtr()));
+  }
 }
 
 GpuProcessTransportFactory::~GpuProcessTransportFactory() {
@@ -285,15 +293,11 @@ ui::ContextFactory* GpuProcessTransportFactory::AsContextFactory() {
 }
 
 gfx::GLSurfaceHandle GpuProcessTransportFactory::CreateSharedSurfaceHandle() {
-  scoped_refptr<cc::ContextProvider> provider =
-      SharedMainThreadContextProvider();
-  if (!provider.get())
+  if (!GpuDataManagerImpl::GetInstance()->CanUseGpuBrowserCompositor())

[piman, 2013/12/11 01:14:03]

In the rest of the patch, we're essentially assuming the GLSurfaceHandle doesn't
change anymore. However, CanUseGpuBrowserCompositor can start succeeding, and
then failing after a few GPU crashes, at which point we'll blacklist the GPU (on
desktop).
When that happens, this will return a different GLSurfaceHandle, that would
cause CreateViewCommandBuffer from the renderer to fail.

That being said, maybe the conditions that lead to this are such that:
1- we only transition from accelerated to non-accelerated
2- when we do, the renderer will also always stop trying to use GPU acceleration

If that's the case, then the patch can simplify code further, and we can pretty
much remove all the CreateViewCommandBuffer delaying logic - see other comments
in the CL

If that is not the case, then we need a chance for the UI to cause a
CreateViewCommandBuffer failure to the renderer, because we can't support the
renderer using GL and the UI to use software. That needs some kind of
throttling, and the current code wouldn't do that correctly I think. However,
we're down to a single bit of information that'd be valid for all renderers, so
maybe this can be handled in a simpler way.

[no sievers, 2013/12/11 01:49:24]

I think on windows with SwiftShader it's possible that
CanUseGpuBrowserCompositor() initially fails and later succeeds :/

     return gfx::GLSurfaceHandle();
-  typedef WebGraphicsContext3DCommandBufferImpl WGC3DCBI;
-  WGC3DCBI* context = static_cast<WGC3DCBI*>(provider->Context3d());
+
   gfx::GLSurfaceHandle handle = gfx::GLSurfaceHandle(
       gfx::kNullPluginWindow, gfx::TEXTURE_TRANSPORT);
-  handle.parent_gpu_process_id = context->GetGPUProcessID();
   handle.parent_client_id =
       BrowserGpuChannelHostFactory::instance()->GetGpuChannelId();
   return handle;
@@ -493,10 +497,27 @@ void GpuProcessTransportFactory::OnLostMainThreadSharedContext() {
                     observer_list_,
                     OnLostResources());
 
+  // This needs to happen after we notified the observers, because until then
+  // we want to block renderers' CreateViewCommandBuffer requests.
+  CauseForGpuLaunch cause =
+      CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE;
+  BrowserGpuChannelHostFactory::instance()->EstablishGpuChannel(
+      cause,
+      base::Bind(&GpuProcessTransportFactory::OnGpuChannelReady,
+                 callback_factory_.GetWeakPtr()));
+
   // Kill things that use the shared context before killing the shared context.
   lost_gl_helper.reset();
   lost_offscreen_compositor_contexts = NULL;
   lost_shared_main_thread_contexts  = NULL;
 }
 
+void GpuProcessTransportFactory::OnGpuChannelReady() {

[piman, 2013/12/11 01:14:03]

nit: this could be static, so you wouldn't need weakptrs above.

+  for (RenderProcessHost::iterator i(RenderProcessHost::AllHostsIterator());
+       !i.IsAtEnd();
+       i.Advance()) {
+    i.GetCurrentValue()->OnParentGpuChannelEstablished();
+  }
+}
+
 }  // namespace content