Adding DRP specfic UMA for FirstContentfulPaint

content/browser/frame_host/navigation_request.h

Index: content/browser/frame_host/navigation_request.h
diff --git a/content/browser/frame_host/navigation_request.h b/content/browser/frame_host/navigation_request.h
index 7d3744c3b8c0ab67bee336ab407865ce78fc0911..c8bb29613a1831eb725568ec6aa831858727b426 100644
--- a/content/browser/frame_host/navigation_request.h
+++ b/content/browser/frame_host/navigation_request.h
@@ -16,23 +16,25 @@
 #include "content/common/navigation_params.h"
 #include "content/public/browser/navigation_throttle.h"
 
 namespace content {
 
 class FrameNavigationEntry;
 class FrameTreeNode;
 class NavigationControllerImpl;
 class NavigationHandleImpl;
 class NavigationURLLoader;
+class NavigationData;
 class NavigatorDelegate;
 class ResourceRequestBody;
 class SiteInstanceImpl;
+class StreamHandle;
 struct NavigationRequestInfo;
 
 // PlzNavigate
 // A UI thread object that owns a navigation request until it commits. It
 // ensures the UI thread can start a navigation request in the
 // ResourceDispatcherHost (that lives on the IO thread).
 // TODO(clamy): Describe the interactions between the UI and IO thread during
 // the navigation following its refactoring.
 class CONTENT_EXPORT NavigationRequest : public NavigationURLLoaderDelegate {
  public:
@@ -166,22 +168,24 @@ class CONTENT_EXPORT NavigationRequest : public NavigationURLLoaderDelegate {
                     const RequestNavigationParams& request_params,
                     scoped_refptr<ResourceRequestBody> body,
                     bool browser_initiated,
                     const FrameNavigationEntry* frame_navigation_entry,
                     const NavigationEntryImpl* navitation_entry);
 
   // NavigationURLLoaderDelegate implementation.
   void OnRequestRedirected(
       const net::RedirectInfo& redirect_info,
       const scoped_refptr<ResourceResponse>& response) override;
-  void OnResponseStarted(const scoped_refptr<ResourceResponse>& response,
-                         std::unique_ptr<StreamHandle> body) override;
+  void OnResponseStarted(
+      const scoped_refptr<ResourceResponse>& response,
+      std::unique_ptr<StreamHandle> body,
+      std::unique_ptr<NavigationData> navigation_data) override;
   void OnRequestFailed(bool has_stale_copy_in_cache, int net_error) override;
   void OnRequestStarted(base::TimeTicks timestamp) override;
 
   // Called when the NavigationThrottles have been checked by the
   // NavigationHandle.
   void OnStartChecksComplete(NavigationThrottle::ThrottleCheckResult result);
   void OnRedirectChecksComplete(NavigationThrottle::ThrottleCheckResult result);
   void OnWillProcessResponseChecksComplete(
       NavigationThrottle::ThrottleCheckResult result);