PlzNavigate: add initial traces for new TBM benchmarks.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 25f1e1dd42678fc17438528ec72583c05ed071d1..cf9a1c2eac92972228215da94d367f3cd5f0c161 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -1133,8 +1133,9 @@ void RenderFrameHostImpl::OnBeforeUnloadACK(
     bool proceed,
     const base::TimeTicks& renderer_before_unload_start_time,
     const base::TimeTicks& renderer_before_unload_end_time) {
-  TRACE_EVENT_ASYNC_END0(
-      "navigation", "RenderFrameHostImpl::BeforeUnload", this);
+  TRACE_EVENT_ASYNC_END1("navigation", "RenderFrameHostImpl BeforeUnload", this,
+                         "FrameTreeNode id",
+                         frame_tree_node_->frame_tree_node_id());
   DCHECK(!GetParent());
   // If this renderer navigated while the beforeunload request was in flight, we
   // may have cleared this state in OnDidCommitProvisionalLoad, in which case we
@@ -1923,8 +1924,8 @@ void RenderFrameHostImpl::DispatchBeforeUnload(bool for_navigation) {
         for_navigation, true, base::TimeTicks::Now());
     return;
   }
-  TRACE_EVENT_ASYNC_BEGIN0(
-      "navigation", "RenderFrameHostImpl::BeforeUnload", this);
+  TRACE_EVENT_ASYNC_BEGIN1("navigation", "RenderFrameHostImpl BeforeUnload",
+                           this, "&RenderFrameHostImpl", (void*)this);
 
   // This may be called more than once (if the user clicks the tab close button
   // several times, or if she clicks the tab close button then the browser close