Adds a WebPageScheduler and a WebFrameScheduler

public/platform/WebFrameScheduler.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 WebFrameScheduler_h
+#define WebFrameScheduler_h
+
+#include "WebCommon.h"
+
+#include <string>
+
+namespace blink {
+
+class WebSecurityOrigin;
+class WebTaskRunner;
+
+class BLINK_PLATFORM_EXPORT WebFrameScheduler {
+public:
+    virtual ~WebFrameScheduler() { }
+
+    // The scheduler may throttle tasks associated with offscreen frames.
+    virtual void setFrameVisible(bool) { }
+
+    // Returns the WebTaskRunner for loading tasks.
+    // WebFrameScheduler owns the returned WebTaskRunner.
+    virtual WebTaskRunner* loadingTaskRunner() { return nullptr; }
+
+    // Returns the WebTaskRunner for timer tasks.
+    // WebFrameScheduler owns the returned WebTaskRunner.
+    virtual WebTaskRunner* timerTaskRunner() { return nullptr; }
+
+    // Record the current origin. This is for task attribution in tracing.
+    virtual void setFrameOrigin(const WebSecurityOrigin*) { }
+};
+
+} // namespace blink
+
+#endif // WebFrameScheduler_h