Notify the renderer if a history navigation has no subframe items.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 83214dd34566f49df10aae8d5c47b837aec7a542..2052b7ceee32f761b7e7f2f58cf504ac2a438c3d 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -1043,6 +1043,7 @@ RenderFrameImpl::RenderFrameImpl(const CreateParams& params)
       render_view_(params.render_view->AsWeakPtr()),
       routing_id_(params.routing_id),
       proxy_routing_id_(MSG_ROUTING_NONE),
+      browser_has_subtree_history_items_(false),
 #if defined(ENABLE_PLUGINS)
       plugin_power_saver_helper_(nullptr),
       plugin_find_handler_(nullptr),
@@ -1165,6 +1166,11 @@ void RenderFrameImpl::Initialize() {
   RenderFrameImpl* parent_frame = RenderFrameImpl::FromWebFrame(
       frame_->parent());
   if (parent_frame) {
+    // Inherit knowledge of whether we need to consult the browser process for
+    // a history item on the first navigation.  This is inherited by further
+    // subframes and cleared at didStopLoading.
+    browser_has_subtree_history_items_ =
+        parent_frame->browser_has_subtree_history_items_;
     is_using_lofi_ = parent_frame->IsUsingLoFi();
     effective_connection_type_ = parent_frame->getEffectiveConnectionType();
   }
@@ -4820,6 +4826,12 @@ void RenderFrameImpl::didStartLoading(bool to_different_document) {
 void RenderFrameImpl::didStopLoading() {
   TRACE_EVENT1("navigation,rail", "RenderFrameImpl::didStopLoading",
                "id", routing_id_);
+
+  // Any subframes created after this point won't be considered part of the
+  // current history navigation (if this was one), so we don't need to track
+  // this state anymore.
+  browser_has_subtree_history_items_ = false;
+
   render_view_->FrameDidStopLoading(frame_);
   Send(new FrameHostMsg_DidStopLoading(routing_id_));
 }
@@ -4964,10 +4976,12 @@ WebNavigationPolicy RenderFrameImpl::decidePolicyForNavigation(
   }
 
   // In OOPIF-enabled modes, back/forward navigations in newly created subframes
-  // should be sent to the browser in case there is a matching
-  // FrameNavigationEntry.  If none is found, fall back to the default url.
+  // should be sent to the browser if there is a chance there is a matching
+  // FrameNavigationEntry.  If none is found (or if the browser has indicated it
+  // has no subtree history items), fall back to loading the default url.
   if (SiteIsolationPolicy::UseSubframeNavigationEntries() &&
-      info.isHistoryNavigationInNewChildFrame && is_content_initiated) {
+      info.isHistoryNavigationInNewChildFrame && is_content_initiated &&
+      browser_has_subtree_history_items_) {
     // Don't do this if |info| also says it is a client redirect, in which case
     // JavaScript on the page is trying to interrupt the history navigation.
     if (!info.isClientRedirect) {
@@ -5571,6 +5585,11 @@ void RenderFrameImpl::NavigateInternal(
                         : blink::WebFrameLoadType::BackForward;
         should_load_request = true;
 
+        // Remember whether we should consult the browser process for any
+        // subframes created during this history navigation.
+        browser_has_subtree_history_items_ =
+            request_params.has_subtree_history_items;
+
         if (history_load_type == blink::WebHistorySameDocumentLoad) {
           // If this is marked as a same document load but we haven't committed
           // anything, treat it as a new load.  The browser shouldn't let this