cc: Route offscreen context creation for compositor to the browser.

cc/single_thread_proxy.cc

Index: cc/single_thread_proxy.cc
diff --git a/cc/single_thread_proxy.cc b/cc/single_thread_proxy.cc
index 40b7ad2019677ff864d42c238e8f7b056bc63b71..39d5ea021a00d49f281e2ab770d41834adcccf54 100644
--- a/cc/single_thread_proxy.cc
+++ b/cc/single_thread_proxy.cc
@@ -139,6 +139,12 @@ bool SingleThreadProxy::recreateOutputSurface()
     scoped_ptr<OutputSurface> outputSurface = m_layerTreeHost->createOutputSurface();
     if (!outputSurface.get())
         return false;
+    WebKit::WebGraphicsContext3D* offscreenContext3d = NULL;
+    if (m_RendererCapabilitiesForMainThread.usingOffscreenContext3d && m_layerTreeHost->needsOffscreenContext()) {
+        offscreenContext3d = m_layerTreeHost->client()->OffscreenContext3dForMainThread();
+        if (!offscreenContext3d)
+            return false;
+    }
 
     bool initialized;
     {
@@ -148,6 +154,7 @@ bool SingleThreadProxy::recreateOutputSurface()
         initialized = m_layerTreeHostImpl->initializeRenderer(outputSurface.Pass());
         if (initialized) {
             m_RendererCapabilitiesForMainThread = m_layerTreeHostImpl->rendererCapabilities();
+            m_layerTreeHostImpl->resourceProvider()->setContext3dForGrContext(offscreenContext3d);
         }
     }
 
@@ -196,8 +203,7 @@ void SingleThreadProxy::doCommit(scoped_ptr<ResourceUpdateQueue> queue)
                 NULL,
                 Proxy::mainThread(),
                 queue.Pass(),
-                m_layerTreeHostImpl->resourceProvider(),
-                hasImplThread());
+                m_layerTreeHostImpl->resourceProvider());
         updateController->finalize();
 
         m_layerTreeHost->finishCommitOnImplThread(m_layerTreeHostImpl.get());
@@ -368,6 +374,11 @@ bool SingleThreadProxy::commitAndComposite()
     if (!m_layerTreeHost->initializeRendererIfNeeded())
         return false;
 
+    WebKit::WebGraphicsContext3D* offscreenContext3d = NULL;
+    if (m_RendererCapabilitiesForMainThread.usingOffscreenContext3d && m_layerTreeHost->needsOffscreenContext()) {
+        offscreenContext3d = m_layerTreeHost->client()->OffscreenContext3dForMainThread();
+    }
+
     m_layerTreeHost->contentsTextureManager()->unlinkAndClearEvictedBackings();
 
     scoped_ptr<ResourceUpdateQueue> queue = make_scoped_ptr(new ResourceUpdateQueue);
@@ -375,18 +386,20 @@ bool SingleThreadProxy::commitAndComposite()
 
     m_layerTreeHost->willCommit();
     doCommit(queue.Pass());
-    bool result = doComposite();
+    bool result = doComposite(offscreenContext3d);
     m_layerTreeHost->didBeginFrame();
     return result;
 }
 
-bool SingleThreadProxy::doComposite()
+    bool SingleThreadProxy::doComposite(WebKit::WebGraphicsContext3D* offscreenContext3d)
 {
     DCHECK(!m_outputSurfaceLost);
     {
         DebugScopedSetImplThread impl(this);
         base::AutoReset<bool> markInside(&m_insideDraw, true);
 
+        m_layerTreeHostImpl->resourceProvider()->setContext3dForGrContext(offscreenContext3d);
+
         if (!m_layerTreeHostImpl->visible())
             return false;