[Android History] List item shadows and width constrained styling

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

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2016 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. -->
 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:orientation="vertical" >
+    android:orientation="vertical"
+    android:layout_marginBottom="8dp" >
 
     <org.chromium.ui.widget.TextViewWithClickableSpans
         android:id="@+id/signed_in_not_synced"
         style="@style/PrivacyDisclaimerText" />
 
    <org.chromium.ui.widget.TextViewWithClickableSpans
         android:id="@+id/signed_in_synced"
         style="@style/PrivacyDisclaimerText" />
 
    <org.chromium.ui.widget.TextViewWithClickableSpans
         android:id="@+id/other_forms_of_browsing_history"
         style="@style/PrivacyDisclaimerText" />
 
     <FrameLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_marginTop="16dp"
-        android:layout_marginBottom="8dp"
-        android:background="@android:color/white" >
+        android:background="@drawable/list_item_single" >
 
         <Button
             android:id="@+id/clear_browsing_data_button"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             style="@style/ButtonCompatBorderless"
             android:paddingTop="16dp"
             android:paddingBottom="16dp"
             android:paddingStart="16dp"
             android:paddingEnd="16dp"
             android:gravity="center_vertical|start"
             android:text="@string/open_clear_browsing_data_dialog_button"
             android:textAllCaps="true"
             android:textColor="@color/history_cbd_button_tint"
             android:textSize="16sp" />
 
     </FrameLayout>
 </LinearLayout>