Adds a WebPageScheduler and a WebFrameScheduler

public/platform/WebPageScheduler.h

+// Copyright 2015 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.
+
+#ifndef WebPageScheduler_h
+#define WebPageScheduler_h
+
+#include "WebCommon.h"
+
+namespace blink {
+
+class WebFrameScheduler;
+
+class BLINK_PLATFORM_EXPORT WebPageScheduler {
+public:
+    virtual ~WebPageScheduler() { }
+
+    // The scheduler may throttle tasks associated with backgound pages.
+    virtual void setPageInBackground(bool) { }
+
+    // Creaters a new WebFrameScheduler, the caller is responsible for deleting it.
+    WebFrameScheduler* createFrameScheduler() { return nullptr; }
+};
+
+} // namespace blink
+
+#endif // WebPageScheduler_h