PlzNavigate: add dump to understand pdf navigation cancellation

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 <utility>
 
 #include "base/memory/ptr_util.h"
 #include "content/browser/appcache/appcache_navigation_handle.h"
@@ skipping 592 matching lines @@
   // WebUI backend won't find a handler for them. They will be processed in the
   // renderer, however do not discard the pending entry so that the URL bar
   // shows them correctly.
   if (!IsRendererDebugURL(common_params_.url)) {
     frame_tree_node_->navigator()->DiscardPendingEntryIfNeeded(
         navigation_handle_.get());
   }
 
   // If the request was canceled by the user do not show an error page.
   if (net_error == net::ERR_ABORTED) {
+    // TODO(clamy): Remove this once we understand the root cause of
+    // crbug.com/709771.
+    if (common_params_.url.spec().find(".pdf") != std::string::npos)

[nasko, 2017/04/17 21:30:05]

Shouldn't this be searching only at the end of the path component? Otherwise
anything in the query string or the domain part can trip it, which I think is a
bit too lax.

[clamy, 2017/04/18 15:29:55]

Done.

+      base::debug::DumpWithoutCrashing();
+
     frame_tree_node_->ResetNavigationRequest(false, true);
     return;
   }
 
   // There are two types of error pages that need to be handled differently.
   // * Error pages resulting from blocking the request, because the original
   //   document wasn't even allowed to make the request. In such case,
   //   the error pages should be committed in the process of the original
   //   document, to avoid creating a process for the destination.
   // * Error pages resulting from either network outage (no network, DNS
@@ skipping 219 matching lines @@
   DCHECK_EQ(request_params_.has_user_gesture, begin_params_.has_user_gesture);
 
   render_frame_host->CommitNavigation(response_.get(), std::move(body_),
                                       std::move(handle_), common_params_,
                                       request_params_, is_view_source_);
 
   frame_tree_node_->ResetNavigationRequest(true, true);
 }
 
 }  // namespace content