Add some tracing to NewTabPage.

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java
index f1987f2aa7a9e4b4669e1ace35c31ad9ae82c3bd..3a840a17d7ffd1bb17ddf178a9ef972b2cdb2afe 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java
@@ -20,6 +20,7 @@ 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;
@@ -418,6 +419,7 @@ public class NewTabPage
      */
     public NewTabPage(ChromeActivity activity, Tab tab, TabModelSelector tabModelSelector) {
         mConstructedTimeNs = System.nanoTime();
+        TraceEvent.begin(TAG);
 
         mTab = tab;
         mTabModelSelector = tabModelSelector;
@@ -491,6 +493,7 @@ public class NewTabPage
         RecordHistogram.recordBooleanHistogram(
                 "NewTabPage.MobileIsUserOnline", NetworkChangeNotifier.isOnline());
         NewTabPageUma.recordLoadType(activity);
+        TraceEvent.end(TAG);
     }
 
     private static MostVisitedSites buildMostVisitedSites(Profile profile) {