Add signalSyncPoint to the WebGraphicsContext3D command buffer impls.

cc/resources/sync_point_helper.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/resources/sync_point_helper.h"
+
+#include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
+
+namespace cc {
+
+class SignalSyncPointCallbackClass
+    : public WebKit::WebGraphicsContext3D::WebGraphicsSyncPointCallback {
+ public:
+  explicit SignalSyncPointCallbackClass(const base::Closure& closure)
+      : closure_(closure) {}
+
+  virtual void onSyncPointReached() {
+    if (!closure_.is_null())
+      closure_.Run();
+  }
+
+ private:
+  base::Closure closure_;
+};
+
+void SyncPointHelper::SignalSyncPoint(
+    WebKit::WebGraphicsContext3D* context3d,
+    unsigned sync_point,
+    const base::Closure& closure) {
+  SignalSyncPointCallbackClass* callback_class =
+      new SignalSyncPointCallbackClass(closure);
+
+  // Pass ownership of the CallbackClass to WebGraphicsContext3D.
+  context3d->signalSyncPoint(sync_point, callback_class);
+}
+
+}  // namespace cc