Prevent browser thumbnailer from trying to read from frontbuffer (surface texture) when none exists.

content/browser/renderer_host/test_render_view_host.cc

 // 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.
 
 #include "content/browser/renderer_host/test_backing_store.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
 #include "content/browser/site_instance_impl.h"
 #include "content/browser/web_contents/navigation_controller_impl.h"
 #include "content/browser/web_contents/test_web_contents.h"
 #include "content/common/view_messages.h"
@@ skipping 51 matching lines @@
 }
 
 gfx::NativeViewAccessible TestRenderWidgetHostView::GetNativeViewAccessible() {
   return NULL;
 }
 
 bool TestRenderWidgetHostView::HasFocus() const {
   return true;
 }
 
+bool TestRenderWidgetHostView::IsSurfaceAvailableForCopy() const {
+  return true;
+}
+
 void TestRenderWidgetHostView::Show() {
   is_showing_ = true;
 }
 
 void TestRenderWidgetHostView::Hide() {
   is_showing_ = false;
 }
 
 bool TestRenderWidgetHostView::IsShowing() {
   return is_showing_;
@@ skipping 246 matching lines @@
 
 TestRenderViewHost* RenderViewHostImplTestHarness::active_test_rvh() {
   return static_cast<TestRenderViewHost*>(active_rvh());
 }
 
 TestWebContents* RenderViewHostImplTestHarness::contents() {
   return static_cast<TestWebContents*>(web_contents());
 }
 
 }  // namespace content