Adding DRP specfic UMA for FirstContentfulPaint

content/public/test/web_contents_tester.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_TEST_WEB_CONTENTS_TESTER_H_
 #define CONTENT_PUBLIC_TEST_WEB_CONTENTS_TESTER_H_
 
 #include <string>
 
 #include "content/public/browser/site_instance.h"
 #include "ui/base/page_transition_types.h"
 
 class GURL;
 
 namespace content {
 
 class BrowserContext;
+class NavigationData;
+class NavigationHandle;
 class RenderFrameHost;
 class RenderViewHost;
 class WebContents;
 struct Referrer;
 
 // This interface allows embedders of content/ to write tests that depend on a
 // test version of WebContents.  This interface can be retrieved from any
 // WebContents that was retrieved via a call to
 // RenderViewHostTestHarness::GetWebContents() (directly or indirectly) or
 // constructed explicitly via CreateTestWebContents.
@@ skipping 82 matching lines @@
                                const GURL& url,
                                ui::PageTransition transition) = 0;
   virtual void TestDidNavigateWithReferrer(RenderFrameHost* render_frame_host,
                                            int page_id,
                                            int nav_entry_id,
                                            bool did_create_new_entry,
                                            const GURL& url,
                                            const Referrer& referrer,
                                            ui::PageTransition transition) = 0;
 
+  // Sets NavgationData on |navigation_handle|.
+  virtual void SetNavigationData(
+      NavigationHandle* navigation_handle,
+      std::unique_ptr<NavigationData> navigation_data) = 0;

[nasko, 2016/05/02 22:02:49]

Is there no other way to invoke the functionality from outside of content/
without explicit set method?

[RyanSturm, 2016/05/02 23:02:56]

I wanted to cast NavigationHandle to NavigationHandleImpl in the test itself,
but that seemed wrong because navigation_handle_impl.h is not in public/. I
didn't see another way to do this without being in content/ code, so there would
need to be a test method somewhere.

+
   // Returns headers that were passed in the previous SaveFrameWithHeaders(...)
   // call.
   virtual const std::string& GetSaveFrameHeaders() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_WEB_CONTENTS_TESTER_H_