Add time-to-network histogram considering browser side navigation

content/browser/frame_host/navigator.h

Index: content/browser/frame_host/navigator.h
diff --git a/content/browser/frame_host/navigator.h b/content/browser/frame_host/navigator.h
index e25671d0f1a42f046f5db8108755b1623df27e71..ce580d7310e1c247b9ae9887ed5d5d6d1836cd22 100644
--- a/content/browser/frame_host/navigator.h
+++ b/content/browser/frame_host/navigator.h
@@ -6,6 +6,7 @@
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_H_
 
 #include "base/memory/ref_counted.h"
+#include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_controller.h"
 #include "ui/base/window_open_disposition.h"
@@ -115,6 +116,11 @@ class CONTENT_EXPORT Navigator : public base::RefCounted<Navigator> {
   virtual void CommitNavigation(RenderFrameHostImpl* render_frame_host,
                                 const NavigationBeforeCommitInfo& info) {};
 
+  // Called when the first resource request for a given navigation is executed
+  // so that it can be tracked into an histogram.
+  virtual void LogResourceRequestTime(
+    base::TimeTicks timestamp, const GURL& url) {};
+
  protected:
   friend class base::RefCounted<Navigator>;
   virtual ~Navigator() {}