Ensure that when a new navigation cancels an existing one, the old navigation's DidFinishNavigati...

content/browser/frame_host/frame_tree_node.cc

Index: content/browser/frame_host/frame_tree_node.cc
diff --git a/content/browser/frame_host/frame_tree_node.cc b/content/browser/frame_host/frame_tree_node.cc
index de1df6f7b5efef341dddfa48a57c8b324b3b1400..5cde38fb9c146cb462eecf55a63f2c22b393c99e 100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -383,8 +383,14 @@ void FrameTreeNode::CreatedNavigationRequest(
   // There's no need to reset the state: there's still an ongoing load, and the
   // RenderFrameHostManager will take care of updates to the speculative
   // RenderFrameHost in DidCreateNavigationRequest below.
-  if (was_previously_loading)
+  if (was_previously_loading) {
+    if (navigation_request_) {
+      // Mark the old request as aborted.
+      navigation_request_->navigation_handle()->set_net_error_code(

[Charlie Reis, 2017/03/24 20:11:09]

I'm curious if this belongs in ResetNavigationRequest, since several other call
sites do this as well.  Looks like there's 16 call sites, so I wonder how many
of the other ones need it.

Looking closer, I suppose CommitNavigation is one that definitely doesn't need
it, and it might be unfortunate to add yet another bool parameter to
ResetNavigationRequest.  Still, I wouldn't be surprised if there are more places
that need this.

[jam, 2017/03/24 22:08:26]

That's a good question; I didn't see any obvious places in the other callsites,
but I didn't test with and without PlzNavigate to see what happens. Here are the
callsites that don't already have setters, and should probably be audited. I've
filed https://bugs.chromium.org/p/chromium/issues/detail?id=705119

NavigationRequest::OnRequestRedirected
-FilterURL fails

NavigationRequest::OnResponseStarted
-ShouldTransferNavigation returns false
  -this only happens for extensions

NavigatorImpl::OnBeginNavigation
-sends a stop IPC, which when it comes back should set the abort error code 

NavigatorImpl::CancelNavigation
RenderFrameHostImpl::DispatchBeforeUnload
RenderFrameHostManager::CancelPendingIfNecessary
-need to investigate what should happen

RenderFrameHostImpl::FailedNavigation
-should already be setting it today

+          net::ERR_ABORTED);
+    }
     ResetNavigationRequest(true, true);
+  }
 
   navigation_request_ = std::move(navigation_request);
   render_manager()->DidCreateNavigationRequest(navigation_request_.get());