Adding DRP specfic UMA for FirstContentfulPaint

chrome/browser/page_load_metrics/page_load_metrics_initialize.cc

Index: chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
index b063cdbc6f6afcb5b14d497dabd6c97839092e9f..cbd0bcf3f65e4bcbc999d4ce0a68a3436628f45e 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
@@ -1,19 +1,20 @@
 // 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.
 
 #include "chrome/browser/page_load_metrics/page_load_metrics_initialize.h"
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/page_load_metrics/observers/aborts_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/google_captcha_observer.h"
 #include "chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "components/page_load_metrics/browser/metrics_web_contents_observer.h"
 #include "components/rappor/rappor_service.h"
 #include "content/public/browser/web_contents.h"
 
@@ -25,20 +26,22 @@ void InitializePageLoadMetricsForWebContents(
       web_contents, base::WrapUnique(new PageLoadMetricsEmbedder()));
 }
 
 PageLoadMetricsEmbedder::~PageLoadMetricsEmbedder() {}
 
 void PageLoadMetricsEmbedder::RegisterObservers(
     page_load_metrics::PageLoadTracker* tracker) {
   // These classes are owned by the metrics.
   tracker->AddObserver(base::WrapUnique(new AbortsPageLoadMetricsObserver()));
   tracker->AddObserver(base::WrapUnique(new CorePageLoadMetricsObserver()));
+  tracker->AddObserver(base::WrapUnique(
+      new data_reduction_proxy::DataReductionProxyMetricsObserver()));
   tracker->AddObserver(base::WrapUnique(new FromGWSPageLoadMetricsObserver()));
   tracker->AddObserver(
       base::WrapUnique(new google_captcha_observer::GoogleCaptchaObserver()));
   // TODO(ricea): Remove this in April 2016 or before. crbug.com/348877
   tracker->AddObserver(
       base::WrapUnique(new chrome::StaleWhileRevalidateMetricsObserver()));
   tracker->AddObserver(
       base::WrapUnique(new DocumentWritePageLoadMetricsObserver()));
   tracker->AddObserver(
       base::WrapUnique(new ServiceWorkerPageLoadMetricsObserver()));