Notification custom layouts: keep settings icon and label together in rtl layout.

* This shrinks the settings button to its contents so there is also no blank space to tap that button
* Screenshots: http://imgur.com/a/zrPta

BUG=577161

Review URL: https://codereview.chromium.org/1580283004

Cr-Commit-Position: refs/heads/master@{#369390}

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

@@ -20,6 +20,7 @@
   |_____________________________________________________|
 -->
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="wrap_content">
 
@@ -126,6 +127,7 @@
             style="@style/WebNotificationDivider"/>
 
         <RelativeLayout
+            tools:ignore="RelativeOverlap"
             android:layout_width="match_parent"
             android:layout_height="wrap_content">
 
@@ -142,14 +144,13 @@
 
             <Button
                 android:id="@+id/origin"
-                android:layout_width="match_parent"
+                android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_marginEnd="8dp"
                 android:layout_alignParentStart="true"
                 android:layout_alignParentTop="true"
-                android:layout_toStartOf="@+id/small_icon_footer"
                 android:minHeight="40dp"
                 android:gravity="start|center_vertical"
+                android:paddingEnd="8dp"
                 android:singleLine="true"
                 android:ellipsize="start"
                 style="@style/WebNotificationSettingsButton"/>

chrome/android/java/res/values-v17/styles.xml

@@ -324,6 +324,8 @@
         parent="@style/WebNotificationButton">
         <item name="android:textAppearance">@style/TextAppearance.StatusBar.EventContent.Line2</item>
         <item name="android:paddingStart">40dp</item>
+        <!-- Margin at the end to avoid overlap with the small icon. -->
+        <item name="android:layout_marginEnd">24dp</item>
     </style>
     <style name="WebNotificationSettingsIcon">
         <item name="android:layout_marginStart">8dp</item>