PlzNavigate: Show error pages when the navigation failed before commit

content/browser/frame_host/navigation_request.cc

 // Copyright 2014 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/navigation_request.h"
 
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/navigation_controller_impl.h"
 #include "content/browser/frame_host/navigation_request_info.h"
@@ skipping 185 matching lines @@
 
 void NavigationRequest::OnResponseStarted(
     const scoped_refptr<ResourceResponse>& response,
     scoped_ptr<StreamHandle> body) {
   DCHECK(state_ == STARTED);
   state_ = RESPONSE_STARTED;
   frame_tree_node_->navigator()->CommitNavigation(frame_tree_node_,
                                                   response.get(), body.Pass());
 }
 
-void NavigationRequest::OnRequestFailed(int net_error) {
+void NavigationRequest::OnRequestFailed(bool in_cache, int net_error) {

[Charlie Reis, 2015/04/09 00:07:30]

Please use the same name as in Navigator (has_stale_copy_in_cache).  These names
sound like they mean very different things.

[clamy, 2015/04/10 14:04:49]

Done.

   DCHECK(state_ == STARTED);
   state_ = FAILED;
-  // TODO(davidben): Network failures should display a network error page.
-  NOTIMPLEMENTED() << " where net_error=" << net_error;
+  frame_tree_node_->navigator()->FailedNavigation(frame_tree_node_, in_cache,
+                                                  net_error);
 }
 
 void NavigationRequest::OnRequestStarted(base::TimeTicks timestamp) {
   frame_tree_node_->navigator()->LogResourceRequestTime(timestamp,
                                                         common_params_.url);
 }
 
 }  // namespace content