Treat external protocols as ABORTED with PlzNavigate

content/browser/frame_host/navigation_handle_impl.cc

 // Copyright 2015 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_handle_impl.h"
 
 #include <iterator>
 
 #include "base/logging.h"
 #include "content/browser/appcache/appcache_navigation_handle.h"
@@ skipping 146 matching lines @@
 NavigationHandleImpl::~NavigationHandleImpl() {
   // Transfer requests that have not matched up with another navigation request
   // from the renderer need to be cleaned up. These are marked as protected in
   // the RDHI, so they do not get cancelled when frames are destroyed.
   if (is_transferring()) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(&NotifyAbandonedTransferNavigation, GetGlobalRequestID()));
   }
 
+  if (!GetContentClient()->browser()->IsHandledURL(url_)) {

[jam, 2017/03/24 14:49:49]

if this was handled by the navigation interceptor in components/, then it should
have got this error code then. Why does it have to be set again? Ted has a
theory that maybe it's being reset when the fallback url is requested? Can you
try loading the fallback url in java on a post task to see if it fixes this?

[wychen, 2017/03/24 15:33:55]

This is obviously the wrong place to inject the error. I'll look into it.
BTW, what do you mean by a post task?

+    net_error_code_ = net::ERR_ABORTED;
+  }
+
   if (!IsRendererDebugURL(url_))
     GetDelegate()->DidFinishNavigation(this);
 
   // Cancel the navigation on the IO thread if the NavigationHandle is being
   // destroyed in the middle of the NavigationThrottles checks.
   if (!IsBrowserSideNavigationEnabled() && !complete_callback_.is_null())
     RunCompleteCallback(NavigationThrottle::CANCEL_AND_IGNORE);
 
   if (IsInMainFrame()) {
     TRACE_EVENT_ASYNC_END2("navigation", "Navigation StartToCommit", this,
@@ skipping 805 matching lines @@
     if (node->current_url().EqualsIgnoringRef(url_)) {
       if (found_self_reference)
         return true;
       found_self_reference = true;
     }
   }
   return false;
 }
 
 }  // namespace content