[Home] Add a bottom navigation bar for the BottomSheet

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

 <?xml version="1.0" encoding="utf-8"?>
 <!-- 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. -->
 
-<merge xmlns:android="http://schemas.android.com/apk/res/android">
+<merge xmlns:android="http://schemas.android.com/apk/res/android"
+       xmlns:app="http://schemas.android.com/apk/res-auto">
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:orientation="vertical">
 
         <android.support.design.widget.CoordinatorLayout
             android:id="@+id/coordinator"
             android:layout_width="match_parent"
             android:layout_height="0dp"
             android:layout_weight="1" >
@@ skipping 46 matching lines @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content" />
 
             <ViewStub
                 android:id="@+id/empty_container_stub"
                 android:inflatedId="@+id/empty_container"
                 android:layout="@layout/empty_background_view_tablet"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent" />
 
+            <org.chromium.chrome.browser.widget.BottomSheetBottomNav

[mdjones, 2017/03/09 16:52:10]

Since this is on the main layout, should we conditionally inflate this or does
visibility="gone" prevent resource usage? 

[Theresa, 2017/03/09 17:55:44]

Done. No, I think resources are still allocated even with visibility="gone"
(based on Android monitor).

+                android:id="@+id/bottom_nav"
+                android:layout_width="match_parent"
+                android:layout_height="@dimen/bottom_nav_height"
+                android:layout_gravity="start|bottom"
+                android:background="@color/appbar_background"
+                app:menu="@menu/bottom_sheet_nav_menu"
+                app:itemIconTint="@color/bottom_nav_tint"
+                app:itemTextColor="@color/bottom_nav_tint"
+                android:visibility="gone" />
+
         </android.support.design.widget.CoordinatorLayout>
 
         <HorizontalScrollView
             android:id="@+id/keyboard_accessory"
             android:layout_height="@dimen/keyboard_accessory_height"
             android:layout_width="match_parent"
             android:background="@drawable/keyboard_accessory_background"
             android:contentDescription="@string/autofill_keyboard_accessory_content_description"
             android:fillViewport="true"
             android:scrollbars="none"
             android:visibility="gone" />
     </LinearLayout>
 
     <!-- This empty view is used as the anchor for custom menu -->
     <View
         android:id="@+id/menu_anchor_stub"
         android:layout_width="0px"
         android:layout_height="0px"
         android:layout_gravity="bottom|start"
         />
 </merge>