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

cc/grcontext_provider.cc

+// Copyright 2013 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.
+
+#include "cc/grcontext_provider.h"
+
+#include "cc/resource_provider.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
+#include "third_party/skia/include/gpu/GrContext.h"
+
+namespace cc {
+
+GrContextProvider::GrContextProvider(ResourceProvider* resource_provider)
+    : resource_provider_(resource_provider),
+      context3d_(NULL),
+      gr_context_(NULL) {
+}
+
+GrContextProvider::~GrContextProvider() {}
+
+void GrContextProvider::BeginUsingContexts() {
+  // Flush the compositor context to ensure that textures there are available
+  // in the shared context.
+  resource_provider_->flush();
+
+  // Make sure ganesh uses the correct GL context.
+  if (context3d())
+    context3d()->makeContextCurrent();
+}
+
+void GrContextProvider::FinishUsingContexts() {
+  // Flush ganesh context so that all the rendered stuff appears on the
+  // texture.
+  if (gr_context())
+    gr_context()->flush();
+  // Flush the GL context so rendering results from this context are
+  // visible in the compositor's context.
+  if (context3d())
+    context3d()->flush();
+}
+
+}  // namespace cc