Record UMA stats for subframes history navigations.

content/browser/frame_host/navigator.cc

Index: content/browser/frame_host/navigator.cc
diff --git a/content/browser/frame_host/navigator.cc b/content/browser/frame_host/navigator.cc
index a70e81704ec46823b959c76c2961da828dadf75f..4985d9ec21cd51c90d12da2c8586ed676749cf11 100644
--- a/content/browser/frame_host/navigator.cc
+++ b/content/browser/frame_host/navigator.cc
@@ -25,7 +25,8 @@ bool Navigator::NavigateToPendingEntry(FrameTreeNode* frame_tree_node,
   return false;
 }
 
-bool Navigator::NavigateNewChildFrame(RenderFrameHostImpl* render_frame_host) {
+bool Navigator::NavigateNewChildFrame(RenderFrameHostImpl* render_frame_host,
+                                      const GURL& default_url) {
   return false;
 }