Create renderers for ExtensionHosts one a time to avoid blocking the UI.

chrome/browser/views/extensions/extension_view.cc

 // Copyright (c) 2006-2009 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/views/extensions/extension_view.h"
 
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_host_view.h"
 #if defined(OS_WIN)
@@ skipping 68 matching lines @@
   // exist in the same z-order as constrained windows.
   RenderWidgetHostViewWin* view_win =
       static_cast<RenderWidgetHostViewWin*>(view);
   HWND hwnd = view_win->Create(GetWidget()->GetNativeView());
   view_win->ShowWindow(SW_SHOW);
   Attach(hwnd);
 #else
   NOTIMPLEMENTED();
 #endif
 
-  host_->CreateRenderView(view);
+  host_->CreateRenderViewSoon(view);
   SetVisible(false);
 
   if (!pending_background_.empty()) {
     render_view_host()->view()->SetBackground(pending_background_);
     pending_background_.reset();
   }
 }
 
 void ExtensionView::ShowIfCompletelyLoaded() {
   // We wait to show the ExtensionView until it has loaded, our parent has
@@ skipping 47 matching lines @@
 
 void ExtensionView::HandleMouseEvent() {
   if (container_)
     container_->OnExtensionMouseEvent(this);
 }
 
 void ExtensionView::HandleMouseLeave() {
   if (container_)
     container_->OnExtensionMouseLeave(this);
 }