[Custom Tabs] Implement Bottombar

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

Index: chrome/android/java/res/layout/main.xml
diff --git a/chrome/android/java/res/layout/main.xml b/chrome/android/java/res/layout/main.xml
index 0d135a74b090720bbf89fefde71744adbedb9e9e..23fd4a4da632b79433e5d61baa6b2d1f72b83072 100644
--- a/chrome/android/java/res/layout/main.xml
+++ b/chrome/android/java/res/layout/main.xml
@@ -24,6 +24,18 @@
             android:fillViewport="true"
             android:scrollbars="none"
             android:visibility="gone" />
+
+        <org.chromium.chrome.browser.widget.FadingShadowView
+            android:id="@+id/bottombar_shadow"
+            android:layout_width="match_parent"
+            android:layout_height="2dp"
+            android:layout_marginTop="-2dp"
+            android:visibility="gone" />
+
+        <ViewStub
+            android:id="@+id/bottombar_stub"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
     </LinearLayout>
 
     <ViewStub
@@ -50,8 +62,7 @@
         android:inflatedId="@+id/empty_container"
         android:layout="@layout/empty_background_view"
         android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        />
+        android:layout_height="match_parent" />
     <!-- This empty view is used as the anchor for custom menu -->
     <View
         android:id="@+id/menu_anchor_stub"