[Custom Tab]Adjust padding for "Powered by Chrome" prompt text

chrome/android/java/res/layout/powered_by_chrome_footer.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. -->
 
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:background="#f5f5f5" >
-    <View
-        android:layout_width="match_parent"
-        android:layout_height="1dp"
-        android:background="#e0e0e0" />
+    android:paddingTop="4dp" >
     <TextView
         android:layout_width="match_parent"
-        android:layout_height="@dimen/menu_footer_height"
-        android:paddingTop="1dp"
+        android:layout_height="wrap_content"
+        android:background="#f5f5f5"
+        android:paddingTop="8dp"
         android:paddingStart="16dp"
         android:paddingEnd="16dp"
+        android:paddingBottom="8dp"
         android:gravity="start|center_vertical"
         android:textSize="12sp"
         android:textColor="#616161"
         android:text="@string/powered_by_chrome_message"
         android:maxLines="1" />
+    <View
+        android:layout_width="match_parent"
+        android:layout_height="1dp"
+        android:background="#e0e0e0" />
 </FrameLayout>