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 b47654839f0f9d70b0729f2c6284d931e1a4ed7b..99ffd087c8419199f37996b2b4382ba2a514bc12 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"
@@ -126,6 +127,11 @@ class CONTENT_EXPORT Navigator : public base::RefCounted<Navigator> {
   virtual void CommitNavigation(RenderFrameHostImpl* render_frame_host,
                                 const NavigationBeforeCommitInfo& info) {};
 
+  // PlzNavigate
+  // Called from the IO thread when the first resource request for a given
+  // navigation is executed so that we can time it.
+  virtual void LogResourceRequestTime(base::TimeTicks timestamp) {};
+
  protected:
   friend class base::RefCounted<Navigator>;
   virtual ~Navigator() {}