[SharingHub] Use a custom divider between the rows

Use a custom divider to correctly match the spec.
http://screen/cGXhXz0KcAX.png

Bug: 1009124
Change-Id: Idd4711681485cfa6d9ea0a77f6e3f6308f338e34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2008357Reviewed-by: Matthew Jones <mdjones@chromium.org>
Reviewed-by: Kristi Park <kristipark@chromium.org>
Commit-Queue: Kyle Milka <kmilka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733033}

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

@@ -5,17 +5,21 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
-    android:divider="?android:dividerHorizontal"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:minHeight="@dimen/min_touch_target_size"
-    android:orientation="vertical"
-    android:showDividers="middle">
+    android:orientation="vertical">
   <android.support.v7.widget.RecyclerView
       android:layout_width="wrap_content"
       android:layout_height="113dp"
       android:minHeight="@dimen/min_touch_target_size"
       android:id="@+id/share_sheet_chrome_apps" />
+  <View
+    android:background="@color/divider_bg_color"
+    android:layout_height="1dp"
+    android:layout_marginLeft="16dp"
+    android:layout_marginRight="16dp"
+    android:layout_width="match_parent" />
   <android.support.v7.widget.RecyclerView
       android:layout_width="wrap_content"
       android:layout_height="113dp"