Replace return button with close button on custom tab toolbar

chrome/android/java/src/org/chromium/chrome/browser/toolbar/Toolbar.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.toolbar;
 
 import android.graphics.Bitmap;
 import android.graphics.Rect;
 import android.view.View;
 import android.view.View.OnClickListener;
@@ skipping 44 matching lines @@
      */
     void setOnNewTabClickHandler(OnClickListener listener);
 
     /**
      * Sets the OnClickListener that will be notified when the bookmark button is pressed.
      * @param listener The callback that will be notified when the bookmark button is pressed.
      */
     void setBookmarkClickHandler(OnClickListener listener);
 
     /**
-     * Sets the OnClickListener to notify when the back button is pressed in a custom tab.
-     * @param listener The callback that will be notified when the back button is pressed.
-     */
-    void setCustomTabReturnClickHandler(OnClickListener listener);
-
-    /**
      * Calculates the {@link Rect} that represents the content area of the location bar.  This
      * rect will be relative to the toolbar.
      * @param outRect The Rect that represents the content area of the location bar.
      */
     void getLocationBarContentRect(Rect outRect);
 
     /**
      * @return Whether any swipe gestures should be ignored for the current Toolbar state.
      */
     boolean shouldIgnoreSwipeGesture();
@@ skipping 27 matching lines @@
      * or animations).
      * @param textureMode Whether or not to be in texture capture mode.
      */
     void setTextureCaptureMode(boolean textureMode);
 
     /**
      * @return Whether a dirty check for invalidation makes sense at this time.
      */
     boolean isReadyForTextureCapture();
 }