Replace return button with close button on custom tab toolbar

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarLayout.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.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
@@ skipping 246 matching lines @@
 
     @Override
     public void setOnTabSwitcherClickHandler(OnClickListener listener) { }
 
     @Override
     public void setOnNewTabClickHandler(OnClickListener listener) { }
 
     @Override
     public void setBookmarkClickHandler(OnClickListener listener) { }
 
-    @Override
-    public void setCustomTabReturnClickHandler(OnClickListener listener) { }
+
+    /**
+     * Sets the OnClickListener to notify when the close button is pressed in a custom tab.
+     * @param listener The callback that will be notified when the close button is pressed.
+     */
+    public void setCustomTabCloseClickHandler(OnClickListener listener) { }
 
     /**
      * Gives inheriting classes the chance to update the visibility of the
      * back button.
      * @param canGoBack Whether or not the current tab has any history to go back to.
      */
     protected void updateBackButtonVisibility(boolean canGoBack) { }
 
     /**
      * Gives inheriting classes the chance to update the visibility of the
@@ skipping 48 matching lines @@
 
         getLocationBar().updateMicButtonState();
     }
 
     /**
      * For extending classes to override and carry out the changes related with the primary color
      * for the current tab changing.
      */
     protected void onPrimaryColorChanged() { }
 
+    /**
+     * Sets the icon resource that the close button in the toolbar (if any) should show.
+     */
+    public void setCloseButtonIcon(int iconRes) { }
+
     @Override
     public void addCustomActionButton(Bitmap buttonSource, OnClickListener listener) { }
 
     /**
      * Triggered when the content view for the specified tab has changed.
      */
     protected void onTabContentViewChanged() {
         NewTabPage ntp = getToolbarDataProvider().getNewTabPageForCurrentTab();
         if (ntp != null) getLocationBar().onTabLoadingNTP(ntp);
     }
@@ skipping 158 matching lines @@
     }
 
     /**
      * Opens hompage in the current tab.
      */
     protected void openHomepage() {
         getLocationBar().hideSuggestions();
         if (mToolbarTabController != null) mToolbarTabController.openHomepage();
     }
 }