Properly recreate swapped out RenderView.

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 <algorithm>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 895 matching lines @@
 
       // When using swapped out RenderFrameHosts, it is possible for the pending
       // RenderFrameHost to be an existing one in swapped out state. Since it
       // has been used to start a navigation, it could have committed a
       // document. Check if |render_frame_host| is already swapped out, to avoid
       // swapping it out again.
       if (!render_frame_host->is_swapped_out())
         render_frame_host->SwapOut(proxy, false);
 
       proxy->TakeFrameHostOwnership(render_frame_host.Pass());
+    } else {
+      // If |render_frame_host| is the RenderViewHost's main frame, it must
+      // be cleared, as it will be deleted at the end of this method.

[Charlie Reis, 2015/10/16 17:02:23]

s/, it must be cleared/, then the RenderViewHost must forget about it/

+      if (frame_tree_node_->IsMainFrame() &&
+          render_frame_host->render_view_host()->GetMainFrame() ==
+              render_frame_host.get()) {
+        render_frame_host->render_view_host()->set_main_frame_routing_id(
+            MSG_ROUTING_NONE);
+      }
     }
   }
 
   if (render_frame_host) {
     // We won't be coming back, so delete this one.
     ShutdownProxiesIfLastActiveFrameInSiteInstance(render_frame_host.get());
     render_frame_host.reset();
   }
 }
 
@@ skipping 897 matching lines @@
     } else {
       proxy = new RenderFrameProxyHost(
           new_render_frame_host->GetSiteInstance(),
           new_render_frame_host->render_view_host(), frame_tree_node_);
       proxy_hosts_->Add(instance->GetId(), make_scoped_ptr(proxy));
       proxy_routing_id = proxy->GetRoutingID();
       proxy->TakeFrameHostOwnership(new_render_frame_host.Pass());
     }
 
     if (frame_tree_node_->IsMainFrame()) {
+      if (!render_view_host->GetMainFrame()) {

[Charlie Reis, 2015/10/16 17:02:23]

What would happen if it had a main frame routing ID for a different frame, or a
non-existing frame?

+        CHECK(!render_view_host->is_active());
+        render_view_host->set_main_frame_routing_id(
+            new_render_frame_host->GetRoutingID());
+      }
+
       success = InitRenderView(render_view_host, proxy_routing_id);
 
       // If we are reusing the RenderViewHost and it doesn't already have a
       // RenderWidgetHostView, we need to create one if this is the main frame.
       if (!swapped_out && !render_view_host->GetView())
         delegate_->CreateRenderWidgetHostViewForRenderManager(render_view_host);
     } else {
       DCHECK(render_view_host->IsRenderViewLive());
     }
 
@@ skipping 798 matching lines @@
 int RenderFrameHostManager::GetOpenerRoutingID(SiteInstance* instance) {
   if (!frame_tree_node_->opener())
     return MSG_ROUTING_NONE;
 
   return frame_tree_node_->opener()
       ->render_manager()
       ->GetRoutingIdForSiteInstance(instance);
 }
 
 }  // namespace content