Adding DRP specfic UMA for FirstContentfulPaint

content/browser/loader/navigation_resource_throttle.h

 // Copyright 2015 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_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
 #define CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/resource_throttle.h"
 
 namespace net {
 class URLRequest;
 }
 
 namespace content {
 
+class ResourceDispatcherHostDelegate;
+
 // This ResourceThrottle is used to convey throttling information to the UI
 // thread during navigations. The UI thread can then use its NavigationThrottle
 // mechanism to interact with the navigation.
 class NavigationResourceThrottle : public ResourceThrottle {
  public:
-  NavigationResourceThrottle(net::URLRequest* request);
+  NavigationResourceThrottle(
+      net::URLRequest* request,
+      ResourceDispatcherHostDelegate* resource_dispatcher_host_delegate);
   ~NavigationResourceThrottle() override;
 
   // ResourceThrottle overrides:
   void WillStartRequest(bool* defer) override;
   void WillRedirectRequest(const net::RedirectInfo& redirect_info,
                            bool* defer) override;
   void WillProcessResponse(bool* defer) override;
   const char* GetNameForLogging() const override;
 
  private:
   void OnUIChecksPerformed(NavigationThrottle::ThrottleCheckResult result);
 
   net::URLRequest* request_;
+  ResourceDispatcherHostDelegate* resource_dispatcher_host_delegate_;
   base::WeakPtrFactory<NavigationResourceThrottle> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationResourceThrottle);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_