Remove limitation that renderer can't send sync IPCs to the UI thread in the browser.

content/browser/renderer_host/render_view_host_impl.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_view_host_impl.h"
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 859 matching lines @@
 
 bool RenderViewHostImpl::SuddenTerminationAllowed() const {
   return sudden_termination_allowed_ ||
       GetProcess()->SuddenTerminationAllowed();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderViewHostImpl, IPC message handlers:
 
 bool RenderViewHostImpl::OnMessageReceived(const IPC::Message& msg) {
-  if (!BrowserMessageFilter::CheckCanDispatchOnUI(msg, GetWidget()))
-    return true;
-
   // Filter out most IPC messages if this renderer is swapped out.
   // We still want to handle certain ACKs to keep our state consistent.
   if (is_swapped_out_) {
     if (!SwappedOutMessages::CanHandleWhileSwappedOut(msg)) {
       // If this is a synchronous message and we decided not to handle it,
       // we must send an error reply, or else the renderer will be stuck
       // and won't respond to future requests.
       if (msg.is_sync()) {
         IPC::Message* reply = IPC::SyncMessage::GenerateReply(&msg);
         reply->set_reply_error();
@@ skipping 468 matching lines @@
   } else {
     render_view_ready_on_process_launch_ = true;
   }
 }
 
 void RenderViewHostImpl::RenderViewReady() {
   delegate_->RenderViewReady(this);
 }
 
 }  // namespace content