Provide shared context to Platform API in renderer.

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index 3913247b420c287226603c197481aafb04343047..20919615e2bca381ab42f61cce493bbfbe49b931 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -17,7 +17,6 @@
 #include "content/renderer/gpu/compositor_thread.h"
 #include "content/renderer/render_thread_impl.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebLayerTreeViewClient.h"
-#include "third_party/WebKit/Source/Platform/chromium/public/WebSharedGraphicsContext3D.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebSize.h"
 #include "webkit/compositor_bindings/web_layer_impl.h"
 #include "webkit/compositor_bindings/web_to_ccinput_handler_adapter.h"
@@ -291,26 +290,23 @@ void RenderWidgetCompositor::didRecreateOutputSurface(bool success) {
 // TODO(danakj): This should go through WebWidget
 WebKit::WebGraphicsContext3D* RenderWidgetCompositor::
     OffscreenContext3dForMainThread() {
-  return WebKit::WebSharedGraphicsContext3D::mainThreadContext();
+  return RenderThreadImpl::current()->OffscreenContext3dForMainThread();
 }
 
 // TODO(danakj): This should go through WebWidget
 WebKit::WebGraphicsContext3D* RenderWidgetCompositor::
     OffscreenContext3dForCompositorThread() {
-  if (!WebKit::WebSharedGraphicsContext3D::haveCompositorThreadContext() &&
-      !WebKit::WebSharedGraphicsContext3D::createCompositorThreadContext())
-    return NULL;
-  return WebKit::WebSharedGraphicsContext3D::compositorThreadContext();
+  return RenderThreadImpl::current()->OffscreenContext3dForCompositorThread();
 }
 
 // TODO(danakj): This should go through WebWidget
 GrContext* RenderWidgetCompositor::OffscreenGrContextForMainThread() {
-  return WebKit::WebSharedGraphicsContext3D::mainThreadGrContext();
+  return RenderThreadImpl::current()->OffscreenGrContextForMainThread();
 }
 
 // TODO(danakj): This should go through WebWidget
 GrContext* RenderWidgetCompositor::OffscreenGrContextForCompositorThread() {
-  return WebKit::WebSharedGraphicsContext3D::compositorThreadGrContext();
+  return RenderThreadImpl::current()->OffscreenGrContextForCompositorThread();
 }
 
 // TODO(jamesr): This should go through WebWidget