Remove RenderViewHost parameter from WebContentsObserver::Did{Start|Stop}Loading.

chrome/browser/tab_contents/navigation_metrics_recorder.cc

 // Copyright (c) 2012 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/tab_contents/navigation_metrics_recorder.h"
 
 #include "base/metrics/histogram.h"
 #include "components/navigation_metrics/navigation_metrics.h"
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/navigation_entry.h"
@@ skipping 15 matching lines @@
 NavigationMetricsRecorder::~NavigationMetricsRecorder() {
 }
 
 void NavigationMetricsRecorder::DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) {
   navigation_metrics::RecordMainFrameNavigation(details.entry->GetVirtualURL(),
                                                 details.is_in_page);
 }
 
-void NavigationMetricsRecorder::DidStartLoading(
-    content::RenderViewHost* render_view_host) {
+void NavigationMetricsRecorder::DidStartLoading() {
 #if defined(OS_WIN) && defined(USE_ASH)
-  if (render_view_host && base::win::GetVersion() >= base::win::VERSION_WIN8) {
-    content::RenderWidgetHostView* rwhv = render_view_host->GetView();
+  content::RenderViewHost* rvh = web_contents()->GetRenderViewHost();
+
+  if (rvh && base::win::GetVersion() >= base::win::VERSION_WIN8) {
+    content::RenderWidgetHostView* rwhv = rvh->GetView();
     if (rwhv) {
       gfx::NativeView native_view = rwhv->GetNativeView();
       if (native_view) {
         chrome::HostDesktopType desktop =
             chrome::GetHostDesktopTypeForNativeView(native_view);
         UMA_HISTOGRAM_ENUMERATION("Win8.PageLoad",
                                   chrome::GetWin8Environment(desktop),
                                   chrome::WIN_8_ENVIRONMENT_MAX);
       }
     }
   }
 #endif
 }
-
-