Clean up tinted ImageView subclasses

chrome/android/java/res/layout/title_button_menu_item.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2014 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.
 -->
+
+<!-- Represents a menu item that can display any of the following options:
+     * A text label
+     * A text label with a checkbox indicating that it is enabled or disabled
+     * A text label with an icon
+-->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:chrome="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="?android:attr/listPreferredItemHeightSmall">
     <TextView
         android:id="@+id/title"
         android:layout_width="0dp"
         android:layout_height="match_parent"
         android:layout_gravity="start"
         android:layout_weight="1"
         android:background="?attr/listChoiceBackgroundIndicator"
         android:gravity="center_vertical"
         android:paddingStart="16dp"
         android:paddingEnd="9dp"
         android:singleLine="true"
         android:textAppearance="?android:attr/textAppearanceLargePopupMenu" />
 
+    <!-- Checkbox.  Paddings account for built-in padding from the Android resource. -->
+    <org.chromium.chrome.browser.appmenu.AppMenuItemIcon
+        android:id="@+id/checkbox"
+        android:layout_width="56dp"
+        android:layout_height="match_parent"
+        android:background="?attr/listChoiceBackgroundIndicator"
+        android:paddingStart="12dp"
+        android:paddingEnd="12dp"
+        android:paddingTop="8dp"
+        android:paddingBottom="8dp"
+        android:scaleType="fitCenter"
+        android:src="?android:attr/listChoiceIndicatorMultiple"
+        chrome:chrometint="@null" />
+
+    <!-- Displays an icon. -->
     <org.chromium.chrome.browser.widget.TintedImageButton
         android:id="@+id/button"
         android:layout_width="56dp"
         android:layout_height="match_parent"
         android:background="?attr/listChoiceBackgroundIndicator"
         android:paddingStart="16dp"
         android:paddingEnd="16dp"
         android:paddingTop="12dp"
         android:paddingBottom="12dp"
         android:scaleType="fitCenter"
         chrome:chrometint="@null" />
 </LinearLayout>