Fix InvalidateFullScreen() for the full-screen-polling case.

remoting/host/capturer_linux.cc

 // 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.
 
 #include "remoting/host/capturer.h"
 
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/extensions/Xdamage.h>
 
@@ skipping 245 matching lines @@
 void CapturerLinux::InvalidateRects(const InvalidRects& inval_rects) {
   helper_.InvalidateRects(inval_rects);
 }
 
 void CapturerLinux::InvalidateScreen(const gfx::Size& size) {
   helper_.InvalidateScreen(size);
 }
 
 void CapturerLinux::InvalidateFullScreen() {
   helper_.InvalidateFullScreen();
+  last_buffer_ = NULL;
 }
 
 void CapturerLinux::CaptureInvalidRects(
     CaptureCompletedCallback* callback) {
   scoped_ptr<CaptureCompletedCallback> callback_deleter(callback);
 
   // TODO(lambroslambrou): In the non-DAMAGE case, there should be no need
   // for any X event processing in this class.
   ProcessPendingXEvents();
 
@@ skipping 228 matching lines @@
 }
 
 }  // namespace
 
 // static
 Capturer* Capturer::Create() {
   return new CapturerLinux();
 }
 
 }  // namespace remoting