[bfcache] Add more trace events for bfcache

Restarting bfcached navigations (e.g. when we evict after the document
was restored) is potentially problematic - add trace events to ensure
that the problems are easy to diagnose.

R=alexmos@chromium.org

Change-Id: Ia1a888889e52d9e9a0aaec7119833a851060d234
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1930151
Commit-Queue: Alexander Timin <altimin@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#722412}

content/browser/frame_host/navigation_controller_impl.cc

@@ -2576,6 +2576,7 @@ void NavigationControllerImpl::NavigateToExistingPendingEntry(
   // BackForwardCache:
   // Navigate immediately if the document is in the BackForwardCache.
   if (back_forward_cache_.GetEntry(nav_entry_id)) {
+    TRACE_EVENT0("navigation", "BackForwardCache_CreateNavigationRequest");
     DCHECK_EQ(reload_type, ReloadType::NONE);
     auto navigation_request = CreateNavigationRequestFromEntry(
         root, pending_entry_, pending_entry_->GetFrameEntry(root),

content/browser/frame_host/navigation_request.cc

@@ -3892,6 +3892,8 @@ void NavigationRequest::SetSourceSiteInstanceToInitiatorIfNeeded() {
 }
 
 void NavigationRequest::RestartBackForwardCachedNavigation() {
+  TRACE_EVENT0("navigation",
+               "NavigationRequest::RestartBackForwardCachedNavigation");
   CHECK(IsServedFromBackForwardCache());
   restarting_back_forward_cached_navigation_ = true;
   base::PostTask(
@@ -3901,6 +3903,8 @@ void NavigationRequest::RestartBackForwardCachedNavigation() {
 }
 
 void NavigationRequest::RestartBackForwardCachedNavigationImpl() {
+  TRACE_EVENT0("navigation",
+               "NavigationRequest::RestartBackForwardCachedNavigationImpl");
   RenderFrameHostImpl* rfh = rfh_restored_from_back_forward_cache();
   CHECK(rfh);
   CHECK_EQ(rfh->frame_tree_node()->navigation_request(), this);

content/browser/frame_host/render_frame_host_impl.cc

@@ -1175,6 +1175,7 @@ void RenderFrameHostImpl::AudioContextPlaybackStopped(int audio_context_id) {
 
 // The current frame went into the BackForwardCache.
 void RenderFrameHostImpl::EnterBackForwardCache() {
+  TRACE_EVENT0("navigation", "RenderFrameHostImpl::EnterBackForwardCache");
   DCHECK(IsBackForwardCacheEnabled());
   DCHECK(!is_in_back_forward_cache_);
   is_in_back_forward_cache_ = true;
@@ -1204,6 +1205,7 @@ void RenderFrameHostImpl::EnterBackForwardCache() {
 
 // The frame as been restored from the BackForwardCache.
 void RenderFrameHostImpl::LeaveBackForwardCache() {
+  TRACE_EVENT0("navigation", "RenderFrameHostImpl::LeaveBackForwardCache");
   DCHECK(IsBackForwardCacheEnabled());
   DCHECK(is_in_back_forward_cache_);
   is_in_back_forward_cache_ = false;
@@ -3796,6 +3798,8 @@ void RenderFrameHostImpl::EvictFromBackForwardCacheWithReasons(
     metrics->MarkNotRestoredWithReason(can_store);
 
   if (!in_back_forward_cache) {
+    TRACE_EVENT0("navigation", "BackForwardCache_EvictAfterDocumentRestored");
+
     BackForwardCacheMetrics::RecordEvictedAfterDocumentRestored(
         BackForwardCacheMetrics::EvictedAfterDocumentRestoredReason::
             kByJavaScript);

content/browser/frame_host/render_frame_host_manager.cc

@@ -616,6 +616,8 @@ bool RenderFrameHostManager::DeleteFromPendingList(
 
 void RenderFrameHostManager::RestoreFromBackForwardCache(
     std::unique_ptr<BackForwardCacheImpl::Entry> entry) {
+  TRACE_EVENT0("navigation",
+               "RenderFrameHostManager::RestoreFromBackForwardCache");
   // Matched in CommitPending().
   entry->render_frame_host->GetProcess()->AddPendingView();
 

content/browser/renderer_host/render_view_host_impl.cc

@@ -405,6 +405,7 @@ void RenderViewHostImpl::SetMainFrameRoutingId(int routing_id) {
 }
 
 void RenderViewHostImpl::EnterBackForwardCache() {
+  TRACE_EVENT0("navigation", "RenderViewHostImpl::EnterBackForwardCache");
   FrameTree* frame_tree = GetDelegate()->GetFrameTree();
   frame_tree->UnregisterRenderViewHost(this);
   is_in_back_forward_cache_ = true;
@@ -414,6 +415,7 @@ void RenderViewHostImpl::EnterBackForwardCache() {
 
 void RenderViewHostImpl::LeaveBackForwardCache(
     base::TimeTicks navigation_start) {
+  TRACE_EVENT0("navigation", "RenderViewHostImpl::LeaveBackForwardCache");
   FrameTree* frame_tree = GetDelegate()->GetFrameTree();
   // At this point, the frames |this| RenderViewHostImpl belongs to are
   // guaranteed to be committed, so it should be reused going forward.