Schedule idle handler in the foreground tab based on CPU usage and user activity.

content/renderer/idle_user_detector.h

+// Copyright (c) 2011 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 CONTENT_RENDERER_IDLE_USER_DETECTOR_H_
+#define CONTENT_RENDERER_IDLE_USER_DETECTOR_H_
+
+#include "base/basictypes.h"
+#include "content/public/renderer/render_view_observer.h"
+
+// Class which observes user input events and postpones
+// idle notifications if the user is active.
+class IdleUserDetector : public content::RenderViewObserver {

[ulan, 2011/11/16 14:14:46]

Is overhead of having additional RenderViewObserver too large?

+ public:
+  IdleUserDetector(content::RenderView* render_view);
+  virtual ~IdleUserDetector();
+
+ private:
+  // RenderViewObserver implementation:
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  void OnHandleInputEvent(const IPC::Message& message);
+
+  DISALLOW_COPY_AND_ASSIGN(IdleUserDetector);
+};
+
+#endif  // CONTENT_RENDERER_IDLE_USER_DETECTOR_H_