Adds a list view option for viewing bookmarks

 Bug: 3166319
 This adds a popup menu option to the combined view that allows a
 user to switch between viewing their bookmarks as a grid of thumbnails
 or as a list of bookmarks with favicons.

Change-Id: I6729d477f574a46847dff4b69c1b32d9f63fb37f
diff --git a/res/layout/bookmarks.xml b/res/layout/bookmarks.xml
index fa08353..66a78e8 100644
--- a/res/layout/bookmarks.xml
+++ b/res/layout/bookmarks.xml
@@ -31,6 +31,13 @@
         android:focusable="true"
         android:focusableInTouchMode="true"
         android:numColumns="auto_fit" />
+    <ListView
+        android:id="@+id/list"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:focusable="true"
+        android:focusableInTouchMode="true"
+        android:visibility="gone"/>
     <TextView
         android:id="@android:id/empty"
         android:layout_width="wrap_content"