Update entry page type to include error pages when appropriate.

content/common/frame_messages.h

 // 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.
 
 // IPC messages for interacting with frames.
 // Multiply-included message file, hence no include guard.
 
 #include "content/common/content_export.h"
 #include "content/common/content_param_traits.h"
 #include "content/common/frame_message_enums.h"
@@ skipping 123 matching lines @@
   IPC_STRUCT_MEMBER(int64, post_id)
 
   // Whether the frame navigation resulted in no change to the documents within
   // the page. For example, the navigation may have just resulted in scrolling
   // to a named anchor.
   IPC_STRUCT_MEMBER(bool, was_within_same_page)
 
   // The status code of the HTTP request.
   IPC_STRUCT_MEMBER(int, http_status_code)
 
+  // The URL reachability status.

[Charlie Reis, 2014/09/22 21:43:53]

This comment isn't very helpful for understanding what it's about.  Can we say
this is about error pages, or is this used for other things as well?

[wjmaclean, 2014/09/23 18:42:38]

You got into more detail on this round than I expected ... this was just a
placeholder comment until I found out if the approach was ok.

Fixed.

+  IPC_STRUCT_MEMBER(bool, url_is_unreachable)
+
   // True if the connection was proxied.  In this case, socket_address
   // will represent the address of the proxy, rather than the remote host.
   IPC_STRUCT_MEMBER(bool, was_fetched_via_proxy)
 
   // Serialized history item state to store in the navigation entry.
   IPC_STRUCT_MEMBER(content::PageState, page_state)
 
   // Original request's URL.
   IPC_STRUCT_MEMBER(GURL, original_request_url)
 
@@ skipping 601 matching lines @@
 IPC_MESSAGE_ROUTED0(FrameHostMsg_DidFirstVisuallyNonEmptyPaint)
 
 #if defined(OS_MACOSX) || defined(OS_ANDROID)
 
 // Message to show/hide a popup menu using native controls.
 IPC_MESSAGE_ROUTED1(FrameHostMsg_ShowPopup,
                     FrameHostMsg_ShowPopup_Params)
 IPC_MESSAGE_ROUTED0(FrameHostMsg_HidePopup)
 
 #endif