Cross-process iframe accessibility.

content/renderer/accessibility/renderer_accessibility.cc

Index: content/renderer/accessibility/renderer_accessibility.cc
diff --git a/content/renderer/accessibility/renderer_accessibility.cc b/content/renderer/accessibility/renderer_accessibility.cc
index 1bf402267815b09443aad20f6415c70ce24dc527..e3522b641161d0182a2be69e3f4c2f604328b9f7 100644
--- a/content/renderer/accessibility/renderer_accessibility.cc
+++ b/content/renderer/accessibility/renderer_accessibility.cc
@@ -26,12 +26,8 @@ RendererAccessibility::~RendererAccessibility() {
 }
 
 WebDocument RendererAccessibility::GetMainDocument() {
-  WebView* view = render_frame_->render_view()->GetWebView();
-  WebFrame* main_frame = view ? view->mainFrame() : NULL;
-
-  if (main_frame)
-    return main_frame->document();
-
+  if (render_frame_ && render_frame_->GetWebFrame())
+    return render_frame_->GetWebFrame()->document();
   return WebDocument();
 }