Add NavigationToFirstContentfulPaint UMA for ServiceWorker controlled pages.

chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h b/chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h
similarity index 51%
copy from chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h
copy to chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h
index a24421b2e7a2fed61f9494562618d791f1c18bf3..34f0adabfeb688a136c382e00b14cc139971ea33 100644
--- a/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h
@@ -2,34 +2,27 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_DOCUMENT_WRITE_PAGE_LOAD_METRICS_OBSERVER_H_
-#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_DOCUMENT_WRITE_PAGE_LOAD_METRICS_OBSERVER_H_
+#ifndef CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_SERVICE_WORKER_PAGE_LOAD_METRICS_OBSERVER_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_SERVICE_WORKER_PAGE_LOAD_METRICS_OBSERVER_H_
 
 #include "base/macros.h"
 #include "components/page_load_metrics/browser/page_load_metrics_observer.h"
 
-namespace internal {
-
-// Just expose one metric for tests.
-extern const char kHistogramDocWriteParseStartToFirstContentfulPaint[];
-
-}  // namespace internal
-
-class DocumentWritePageLoadMetricsObserver
+class ServiceWorkerPageLoadMetricsObserver
     : public page_load_metrics::PageLoadMetricsObserver {
  public:
-  DocumentWritePageLoadMetricsObserver();
+  ServiceWorkerPageLoadMetricsObserver();
   // page_load_metrics::PageLoadMetricsObserver implementation:
   void OnComplete(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& extra_info) override;
 
  private:
-  void LogDocumentWriteEvaluatorData(
+  void LogServiceWorkerHistograms(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& info);
 
-  DISALLOW_COPY_AND_ASSIGN(DocumentWritePageLoadMetricsObserver);
+  DISALLOW_COPY_AND_ASSIGN(ServiceWorkerPageLoadMetricsObserver);
 };
 
-#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_DOCUMENT_WRITE_PAGE_LOAD_METRICS_OBSERVER_H_
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_SERVICE_WORKER_PAGE_LOAD_METRICS_OBSERVER_H_