With --site-per-process, avoid a crash when a subframe process goes away.

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 1414 matching lines @@
   delegate_->RenderViewReady(this);
 }
 
 void RenderViewHostImpl::OnRenderProcessGone(int status, int exit_code) {
   // Keep the termination status so we can get at it later when we
   // need to know why it died.
   render_view_termination_status_ =
       static_cast<base::TerminationStatus>(status);
 
   // Reset frame tree state.
   // TODO(creis): Once subframes can be in different processes, we'll need to

[nasko, 2014/02/11 04:49:16]

nit: This comment is now stale, right?

[Charlie Reis, 2014/02/12 00:27:57]

Ah, of course.  Done.

   // clear just the FrameTreeNodes affected by the crash (and their subtrees).
   main_frame_id_ = -1;
-  delegate_->GetFrameTree()->ResetForMainFrameSwap();
+  delegate_->GetFrameTree()->RenderProcessGone(this);
 
   // Our base class RenderWidgetHost needs to reset some stuff.
   RendererExited(render_view_termination_status_, exit_code);
 
   delegate_->RenderViewTerminated(this,
                                   static_cast<base::TerminationStatus>(status),
                                   exit_code);
 }
 
 void RenderViewHostImpl::OnDidStartProvisionalLoadForFrame(
@@ skipping 817 matching lines @@
 void RenderViewHostImpl::AttachToFrameTree() {
   FrameTree* frame_tree = delegate_->GetFrameTree();
 
   frame_tree->ResetForMainFrameSwap();
   if (main_frame_id() != FrameTreeNode::kInvalidFrameId) {
     frame_tree->OnFirstNavigationAfterSwap(main_frame_id());
   }
 }
 
 }  // namespace content