Adds metric to help assess last_n impact on tab restores.

chrome/android/java/src/org/chromium/chrome/browser/tab/TabWebContentsObserver.java

 // 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.
 
 package org.chromium.chrome.browser.tab;
 
 import android.os.SystemClock;
 import android.support.annotation.IntDef;
 import android.view.View;
 
@@ skipping 130 matching lines @@
 
     @Override
     public void navigationEntryCommitted() {
         if (mTab.getNativePage() != null) {
             mTab.pushNativePageStateToNavigationEntry();
         }
     }
 
     @Override
     public void didFinishLoad(long frameId, String validatedUrl, boolean isMainFrame) {
-        if (isMainFrame) mTab.didFinishPageLoad();
+        if (isMainFrame) mTab.didFinishPageLoad(validatedUrl);
         PolicyAuditor auditor = AppHooks.get().getPolicyAuditor();
         auditor.notifyAuditEvent(
                 mTab.getApplicationContext(), AuditEvent.OPEN_URL_SUCCESS, validatedUrl, "");
     }
 
     @Override
     public void didFailLoad(
             boolean isMainFrame, int errorCode, String description, String failingUrl) {
         mTab.updateThemeColorIfNeeded(true);
         RewindableIterator<TabObserver> observers = mTab.getTabObservers();
@@ skipping 143 matching lines @@
         }
     }
 
     @Override
     public void destroy() {
         MediaCaptureNotificationService.updateMediaNotificationForTab(
                 mTab.getApplicationContext(), mTab.getId(), 0, mTab.getUrl());
         super.destroy();
     }
 }