Set up Mojo connection when RenderFrameHost is reused for new RenderFrame

content/browser/frame_host/render_frame_host_manager.cc

 // Copyright 2013 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/frame_host/render_frame_host_manager.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 168 matching lines @@
     // Note: we don't call InitRenderView here because we are navigating away
     // soon anyway, and we don't have the NavigationEntry for this host.
     delegate_->CreateRenderViewForRenderManager(
         render_frame_host_->render_view_host(), MSG_ROUTING_NONE,
         MSG_ROUTING_NONE, frame_tree_node_->IsMainFrame());
   }
 
   // If the renderer crashed, then try to create a new one to satisfy this
   // navigation request.
   if (!dest_render_frame_host->IsRenderFrameLive()) {
+    // Instruct the destination render frame host to set up a Mojo connection
+    // with the new render frame if necessary.
+    dest_render_frame_host->SetUpMojoIfNeeded();

[nasko, 2014/10/23 15:59:08]

This should move below the InitRenderView call.

[blundell, 2014/10/24 14:42:55]

It's actually important that this be before that call. When the render process
dies on a WebUI site and then a reload occurs, the call to InitRenderView()
indirectly ends up in the //chrome Mojo WebUI code adding the relevant
MojoWebUIController as a Mojo service to the RFH's ServiceRegistry. Thus, the
ServiceRegistry needs to be set up before that flow occurs.

[nasko, 2014/10/24 16:13:11]

Ok. This seems to be important enough that some of the explanation would be good
to be in the comment before the call.

[Charlie Reis, 2014/10/24 16:30:45]

+1.

+
     // Recreate the opener chain.
     int opener_route_id = delegate_->CreateOpenerRenderViewsForRenderManager(
         dest_render_frame_host->GetSiteInstance());
     if (!InitRenderView(dest_render_frame_host->render_view_host(),
                         opener_route_id,
                         MSG_ROUTING_NONE,
                         frame_tree_node_->IsMainFrame()))
       return NULL;
 
     // Now that we've created a new renderer, be sure to hide it if it isn't
@@ skipping 1408 matching lines @@
 void RenderFrameHostManager::DeleteRenderFrameProxyHost(
     SiteInstance* instance) {
   RenderFrameProxyHostMap::iterator iter = proxy_hosts_.find(instance->GetId());
   if (iter != proxy_hosts_.end()) {
     delete iter->second;
     proxy_hosts_.erase(iter);
   }
 }
 
 }  // namespace content