Trace FrameTreeNode Snapshots

content/browser/frame_host/navigator_impl.cc

Index: content/browser/frame_host/navigator_impl.cc
diff --git a/content/browser/frame_host/navigator_impl.cc b/content/browser/frame_host/navigator_impl.cc
index 2e9a114eef9012d0c70904e3f3211b523ec31658..6259f01057bbcf358358cba6ccd76441b8980575 100644
--- a/content/browser/frame_host/navigator_impl.cc
+++ b/content/browser/frame_host/navigator_impl.cc
@@ -494,6 +494,8 @@ void NavigatorImpl::DidNavigate(
   if (!did_navigate)
     return;  // No navigation happened.
 
+  render_frame_host->frame_tree_node()->frame_tree()->TraceSnapshot();

[clamy, 2015/10/26 14:45:13]

I think this should move to RenderFrameHostManager::CommitPendingIfNecessary
when we commit or destroy the pending/speculative RFH. It would also be
interesting to trace the FrameTree when we create/destroy either of those RFH in
RFHM::GetFrameHostForNavigation and RFHM::UpdateStateForNavigate.

Another option would be to trace the FrameTree when a RFH is created/destroyed
(but we generally try to avoid doing a lot of work in the
constructor/destructor).

[nasko, 2015/10/26 15:59:23]

I would rather not trace in RFHM's method that allocate RFHs that aren't
committed yet. This exposes a level of detail that only few devs in Chrome
understand and is rarely something people care about.
 
This will allow the concept of pending/speculative RFH to leak out, wouldn't it?
I'm against leaking this information.

+
   // DO NOT ADD MORE STUFF TO THIS FUNCTION! Your component should either listen
   // for the appropriate notification (best) or you can add it to
   // DidNavigateMainFramePostCommit / DidNavigateAnyFramePostCommit (only if