Make <webview> use out-of-process iframe architecture.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index c9cbd6689944fbccc878e9e79f505e7f256630e5..47783669bf4f96b44c56ed0ac1658e1061f27572 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -729,6 +729,15 @@ void RenderViewImpl::Initialize(const ViewMsg_New_Params& params,
     main_render_frame_->set_render_frame_proxy(proxy);
   }
 
+  // This breaks postMessage otherwise.
+  //
+  // The following assumption that we can use the WebRemoteFrame as the
+  // main frame doesn't hold for <webview>, because our top level frame
+  // is the guest's main frame. The proxy that created this WebRemoteFrame
+  // is merely a proxy to the guest and is not part of the frame tree.
+  // TODO(lazyboy): Find a solution here since this breaks regular OOPIF.
+  webview()->setMainFrame(main_render_frame_->GetWebFrame());
+  /*
   // In --site-per-process, just use the WebRemoteFrame as the main frame.
   if (command_line.HasSwitch(switches::kSitePerProcess) && proxy) {
     webview()->setMainFrame(proxy->web_frame());
@@ -738,6 +747,7 @@ void RenderViewImpl::Initialize(const ViewMsg_New_Params& params,
   } else {
     webview()->setMainFrame(main_render_frame_->GetWebFrame());
   }
+  */
   main_render_frame_->Initialize();
 
   if (switches::IsTouchDragDropEnabled())