Adding DRP specfic UMA for FirstContentfulPaint

content/browser/frame_host/navigation_user_data.cc

+// Copyright 2014 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.
+
+#include "content/browser/frame_host/navigation_user_data.h"
+
+namespace content {
+
+const void* const kNavigationUserDataKey = &kNavigationUserDataKey;
+
+NavigationUserData::NavigationUserData()
+    : navigation_supports_user_data_(new NavigationSupportsUserData()) {}
+
+NavigationUserData::~NavigationUserData() {}
+
+NavigationSupportsUserData*
+NavigationUserData::get_navigation_supports_user_data() {
+  return navigation_supports_user_data_.get();
+}
+
+scoped_ptr<NavigationSupportsUserData>
+NavigationUserData::take_own_navigation_supports_user_data() {
+  return std::move(navigation_supports_user_data_);
+}
+
+}  // namespace content