[host] add timeout return value for repeated frame

This is to allow a repeat frame without incuring an additional
memory copy when the frame is already in shared memory.

host/ICapture.h

@@ -52,6 +52,7 @@ struct FrameInfo
 enum GrabStatus
 {
   GRAB_STATUS_OK,
+  GRAB_STATUS_TIMEOUT,
   GRAB_STATUS_REINIT,
   GRAB_STATUS_CURSOR,
   GRAB_STATUS_ERROR