Connect to DesktopEnvironment's stubs only when audio/video schedulers are about to be created.

remoting/host/mouse_clamping_filter.h

 // Copyright (c) 2012 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 REMOTING_HOST_MOUSE_CLAMPING_FILTER_H_
 #define REMOTING_HOST_MOUSE_CLAMPING_FILTER_H_
 
 #include "base/compiler_specific.h"
 #include "remoting/protocol/mouse_input_filter.h"
+#include "remoting/protocol/video_stub.h"
 
 namespace remoting {
 
-class VideoFrameCapturer;
-
-// Filtering InputStub implementation which clamps mouse each mouse event to
-// the current dimensions of a VideoFrameCapturer instance before passing
-// them on to the target |input_stub|.
-class MouseClampingFilter : public protocol::MouseInputFilter {
+// Filtering VideoStub implementation which configures a MouseInputFilter to
+// clamp mouse events to fall within the dimensions of the most-recently
+// received video frame.
+class MouseClampingFilter : public protocol::VideoStub {
  public:
-  MouseClampingFilter(VideoFrameCapturer* capturer,
-                      protocol::InputStub* input_stub);
+  MouseClampingFilter(protocol::InputStub* input_stub,
+                      protocol::VideoStub* video_stub);
   virtual ~MouseClampingFilter();
 
-  // InputStub overrides.
-  virtual void InjectMouseEvent(const protocol::MouseEvent& event) OVERRIDE;
+  protocol::InputStub* input_filter() { return &input_filter_; }
+
+  // protocol::VideoStub implementation.
+  virtual void ProcessVideoPacket(scoped_ptr<VideoPacket> video_packet,
+                                  const base::Closure& done) OVERRIDE;
 
  private:
-  VideoFrameCapturer* capturer_;
+  // Clamps mouse event coordinates to the video dimensions.
+  protocol::MouseInputFilter input_filter_;
+
+  protocol::VideoStub* video_stub_;
 
   DISALLOW_COPY_AND_ASSIGN(MouseClampingFilter);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_MOUSE_CLAMPING_FILTER_H_