Implement SmartText selection.

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

 // Copyright 2012 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 android.annotation.SuppressLint;
 import android.annotation.TargetApi;
 import android.app.assist.AssistStructure.ViewNode;
 import android.content.ClipData;
@@ skipping 1627 matching lines @@
         if (mNativeContentViewCore == 0) return;
 
         nativeSendOrientationChangeEvent(mNativeContentViewCore, orientation);
     }
 
     public ActionModeCallbackHelper getActionModeCallbackHelper() {
         return mSelectionPopupController;
     }
 
     private void showSelectActionMode() {
-        if (!mSelectionPopupController.showActionMode()) clearSelection();

[Ted C, 2017/03/20 20:35:50]

What is this change for?  Does this apply in all circumstances or only if
sendsMenuUpdates returns true?

+        mSelectionPopupController.showActionMode();
     }
 
     public void clearSelection() {
         mSelectionPopupController.clearSelection();
     }
 
     /**
      * Ensure the selection is preserved the next time the view loses focus.
      */
     public void preserveSelectionOnNextLossOfFocus() {
@@ skipping 1018 matching lines @@
     private native void nativeSetTextTrackSettings(long nativeContentViewCoreImpl,
             boolean textTracksEnabled, String textTrackBackgroundColor, String textTrackFontFamily,
             String textTrackFontStyle, String textTrackFontVariant, String textTrackTextColor,
             String textTrackTextShadow, String textTrackTextSize);
 
     private native void nativeSetBackgroundOpaque(long nativeContentViewCoreImpl, boolean opaque);
     private native boolean nativeIsTouchDragDropEnabled(long nativeContentViewCoreImpl);
     private native void nativeOnDragEvent(long nativeContentViewCoreImpl, int action, int x, int y,
             int screenX, int screenY, String[] mimeTypes, String content);
 }