Add page load metrics for no-store forward back navigations.

content/browser/frame_host/navigation_handle_impl.h

Index: content/browser/frame_host/navigation_handle_impl.h
diff --git a/content/browser/frame_host/navigation_handle_impl.h b/content/browser/frame_host/navigation_handle_impl.h
index 264bffa5289c14ca41f7bd867563bdfefd1c26a4..677a167e5737b32c0341c197684f7a1ac22d431a 100644
--- a/content/browser/frame_host/navigation_handle_impl.h
+++ b/content/browser/frame_host/navigation_handle_impl.h
@@ -98,6 +98,7 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
   bool IsSamePage() override;
   bool HasCommitted() override;
   bool IsErrorPage() override;
+  const net::HttpResponseHeaders* GetResponseHeaders() override;
   void Resume() override;
   void CancelDeferredNavigation(
       NavigationThrottle::ThrottleCheckResult result) override;
@@ -123,12 +124,6 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
 
   RequestContextType GetRequestContextType() const;
 
-  // Returns the response headers for the request or nullptr if there are none.
-  // This should only be accessed after a redirect was encountered or after the
-  // navigation is ready to commit. The headers returned should not be modified,
-  // as modifications will not be reflected in the network stack.
-  const net::HttpResponseHeaders* GetResponseHeaders();
-
   // Get the unique id from the NavigationEntry associated with this
   // NavigationHandle. Note that a synchronous, renderer-initiated navigation
   // will not have a NavigationEntry associated with it, and this will return 0.