Merge java_staging/src into java/src.

chrome/android/java/src/org/chromium/chrome/browser/document/DocumentMigrationHelper.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.document;
 
 import android.annotation.TargetApi;
 import android.app.Activity;
 import android.app.ActivityManager;
 import android.app.ActivityManager.AppTask;
@@ skipping 467 matching lines @@
             if (toDocumentMode) {
                 migrateTabsFromClassicToDocument(activity, terminateMode);
             } else {
                 migrateTabsFromDocumentToClassic(activity, terminateMode);
             }
         } finally {
             StrictMode.setThreadPolicy(oldPolicy);
         }
     }
 }