Implement SmartText selection.

content/public/android/java/src/org/chromium/content/browser/ContentClassFactory.java

 // Copyright 2017 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.content.browser;
 
-import org.chromium.base.ThreadUtils;
 import org.chromium.ui.base.WindowAndroid;
 
 /**
  * A class factory for content browser layer.
  */
 public class ContentClassFactory {
     private static ContentClassFactory sSingleton;
 
     /**
      * Sets the factory object.
      */
-    public static void set(ContentClassFactory factory) {
-        ThreadUtils.assertOnUiThread();
-
+    public static synchronized void set(ContentClassFactory factory) {

[Tima Vaisburd, 2017/03/27 18:19:46]

Some tests are failing because their setUp() methos is not run on UI thread.
What is the best way to deal with this?

[boliu, 2017/03/27 18:21:55]

fix the tests

[Tima Vaisburd, 2017/03/28 03:02:14]

Used ThreadUtils.runOnUiThreadBlocking() which I overlooked intially. PTAL
again?

         sSingleton = factory;
     }
 
     /**
      * Returns the factory object.
      */
-    public static ContentClassFactory get() {
-        ThreadUtils.assertOnUiThread();
-
+    public static synchronized ContentClassFactory get() {
         if (sSingleton == null) sSingleton = new ContentClassFactory();
         return sSingleton;
     }
 
     /**
      * Constructor.
      */
     protected ContentClassFactory() {}
 
     /**
      * Creates ContextSelectorProvider object.
      */
     public ContextSelectionProvider createContextSelectionProvider(
             ContextSelectionProvider.ResultCallback callback, WindowAndroid windowAndroid) {
         // Implemented by a subclass.
         return null;
     }
 }