Allow shaped-desktop hosts to send shape only when it changes.

remoting/client/plugin/chromoting_instance.h

Index: remoting/client/plugin/chromoting_instance.h
diff --git a/remoting/client/plugin/chromoting_instance.h b/remoting/client/plugin/chromoting_instance.h
index 7f600bb1d9aecb35dc2c87163135479a92fb3039..ba0c7d3d24b4505c06d696604fc13dc819d45e6e 100644
--- a/remoting/client/plugin/chromoting_instance.h
+++ b/remoting/client/plugin/chromoting_instance.h
@@ -131,7 +131,7 @@ class ChromotingInstance : public ClientUserInterface,
   void OnVideoFirstFrameReceived() override;
   void OnVideoSize(const webrtc::DesktopSize& size,
                       const webrtc::DesktopVector& dpi) override;
-  void OnVideoShape(const webrtc::DesktopRegion& shape) override;
+  void OnVideoShape(const webrtc::DesktopRegion* shape) override;
   void OnVideoFrameDirtyRegion(
       const webrtc::DesktopRegion& dirty_region) override;