Set the accessibility ViewProp in OnCreate in addition to Show, because...

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 <algorithm>
 
 #include "base/command_line.h"
 #include "base/i18n/rtl.h"
@@ skipping 823 matching lines @@
 
 LRESULT RenderWidgetHostViewWin::OnCreate(CREATESTRUCT* create_struct) {
   // Call the WM_INPUTLANGCHANGE message handler to initialize the input locale
   // of a browser process.
   OnInputLangChange(0, 0);
   // Marks that window as supporting mouse-wheel messages rerouting so it is
   // scrolled when under the mouse pointer even if inactive.
   props_.push_back(views::SetWindowSupportsRerouteMouseWheel(m_hWnd));
   props_.push_back(new ViewProp(m_hWnd, kRenderWidgetHostViewKey,
                                 static_cast<RenderWidgetHostView*>(this)));
+  // Save away our HWND in the parent window as a property so that the
+  // accessibility code can find it.
+  accessibility_prop_.reset(new ViewProp(GetParent(),
+                                         kViewsNativeHostPropForAccessibility,
+                                         m_hWnd));
+
   return 0;
 }
 
 void RenderWidgetHostViewWin::OnActivate(UINT action, BOOL minimized,
                                          HWND window) {
   // If the container is a popup, clicking elsewhere on screen should close the
   // popup.
   if (close_on_deactivate_ && action == WA_INACTIVE) {
     // Send a windows message so that any derived classes
     // will get a change to override the default handling
@@ skipping 960 matching lines @@
 }
 
 // static
 RenderWidgetHostView*
     RenderWidgetHostView::GetRenderWidgetHostViewFromNativeView(
         gfx::NativeView native_view) {
   return ::IsWindow(native_view) ?
       reinterpret_cast<RenderWidgetHostView*>(
           ViewProp::GetValue(native_view, kRenderWidgetHostViewKey)) : NULL;
 }