If compositor window already exists, then simply return it rather than compla...

chrome/browser/renderer_host/render_widget_host_view_win.cc

 // Copyright (c) 2010 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 "chrome/browser/renderer_host/render_widget_host_view_win.h"
 
 #include "app/l10n_util.h"
 #include "app/l10n_util_win.h"
 #include "app/resource_bundle.h"
 #include "app/view_prop.h"
@@ skipping 1524 matching lines @@
     PaintCompositorHostWindow(hWnd);
     return 0;
   default:
     return DefWindowProc(hWnd, message, wParam, lParam);
   }
 }
 
 // Creates a HWND within the RenderWidgetHostView that will serve as a host
 // for a HWND that the GPU process will create. The host window is used
 // to Z-position the GPU's window relative to other plugin windows.
-gfx::PluginWindowHandle RenderWidgetHostViewWin::CreateCompositorHostWindow() {
-  DCHECK(!compositor_host_window_);
+gfx::PluginWindowHandle RenderWidgetHostViewWin::GetCompositorHostWindow() {
+  // If the window has been created, don't recreate it a second time
+  if (compositor_host_window_)
+    return compositor_host_window_;
+
   static ATOM window_class = 0;
   if (!window_class) {
     WNDCLASSEX wcex;
     wcex.cbSize         = sizeof(WNDCLASSEX);
     wcex.style          = 0;
     wcex.lpfnWndProc    = CompositorHostWindowProc;
     wcex.cbClsExtra     = 0;
     wcex.cbWndExtra     = 0;
     wcex.hInstance      = GetModuleHandle(NULL);
     wcex.hIcon          = 0;
@@ skipping 246 matching lines @@
 }
 
 // static
 RenderWidgetHostView*
     RenderWidgetHostView::GetRenderWidgetHostViewFromNativeView(
         gfx::NativeView native_view) {
   return ::IsWindow(native_view) ?
       reinterpret_cast<RenderWidgetHostView*>(
           ViewProp::GetValue(native_view, kRenderWidgetHostViewKey)) : NULL;
 }