Add some tracing to NewTabPage.

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.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.ntp;
 
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.os.Build;
 import android.support.v4.view.ViewCompat;
 import android.support.v7.widget.RecyclerView;
 import android.text.TextUtils;
 import android.view.LayoutInflater;
 import android.view.View;
 
 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.CommandLine;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
+import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.NativePage;
 import org.chromium.chrome.browser.UrlConstants;
 import org.chromium.chrome.browser.compositor.layouts.content.InvalidationAwareThumbnailProvider;
@@ skipping 378 matching lines @@
     }
 
     /**
      * Constructs a NewTabPage.
      * @param activity The activity used for context to create the new tab page's View.
      * @param tab The Tab that is showing this new tab page.
      * @param tabModelSelector The TabModelSelector used to open tabs.
      */
     public NewTabPage(ChromeActivity activity, Tab tab, TabModelSelector tabModelSelector) {
         mConstructedTimeNs = System.nanoTime();
+        TraceEvent.begin(TAG);
 
         mTab = tab;
         mTabModelSelector = tabModelSelector;
         Profile profile = tab.getProfile();
 
         mSnippetsBridge = new SnippetsBridge(profile);
 
         SuggestionsNavigationDelegateImpl navigationDelegate =
                 new SuggestionsNavigationDelegateImpl(activity, profile, tab, tabModelSelector);
         mNewTabPageManager = new NewTabPageManagerImpl(
@@ skipping 53 matching lines @@
         if (mSnippetsBridge != null) {
             mSnippetsBridge.onNtpInitialized();
         }
 
         DownloadManagerService.getDownloadManagerService(ContextUtils.getApplicationContext())
                 .checkForExternallyRemovedDownloads(/*isOffRecord=*/false);
 
         RecordHistogram.recordBooleanHistogram(
                 "NewTabPage.MobileIsUserOnline", NetworkChangeNotifier.isOnline());
         NewTabPageUma.recordLoadType(activity);
+        TraceEvent.end(TAG);
     }
 
     private static MostVisitedSites buildMostVisitedSites(Profile profile) {
         if (sMostVisitedSitesForTests != null) {
             return sMostVisitedSitesForTests;
         } else {
             return new MostVisitedSites(profile);
         }
     }
 
@@ skipping 249 matching lines @@
     @Override
     public boolean shouldCaptureThumbnail() {
         return mNewTabPageView.shouldCaptureThumbnail();
     }
 
     @Override
     public void captureThumbnail(Canvas canvas) {
         mNewTabPageView.captureThumbnail(canvas);
     }
 }