Tweak UI of profile tab layout

- Change color & shape of indicator.
- Add margin around tab layout.
- Remove divider below the tab layout.

Bug: 188589806
Bug: 188589053
Test: manual visual
Change-Id: I644a4aeb951daa6eb601229fa5f1096dcbdc86ca

res/drawable/tabs_indicator_background.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     Copyright (C) 2021 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<shape
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+
+    <solid android:color="?android:attr/textColorSecondaryInverse"/>
+    <corners android:radius="8dp"/>
+    <size android:height="4dp"/>
+</shape>

res/layout/preference_list_fragment.xml

@@ -19,6 +19,7 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:androidprv="http://schemas.android.com/apk/prv/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/container_material"
     android:orientation="vertical"
@@ -66,19 +67,20 @@
             android:background="@android:color/transparent"
             android:id="@+id/tabs"
             android:layout_width="match_parent"
-            android:layout_height="wrap_content"
+            android:layout_height="48dp"
+            android:layout_marginStart="24dp"
+            android:layout_marginEnd="24dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginBottom="8dp"
             android:layoutDirection="ltr"
             app:tabMaxWidth="0dp"
             app:tabGravity="fill"
             app:tabMode="fixed"
-            app:tabIndicatorColor="@*android:color/accent_device_default"
+            app:tabIndicator="@drawable/tabs_indicator_background"
+            app:tabIndicatorColor="?androidprv:attr/colorAccentPrimaryVariant"
             app:tabSelectedTextColor="@*android:color/accent_device_default"
             app:tabTextAppearance="@style/TextAppearance.Tab"
             app:tabTextColor="?android:attr/textColorSecondary"/>
-        <View
-            android:layout_width="match_parent"
-            android:layout_height="1dp"
-            android:background="?android:attr/listDivider"/>
 
         <androidx.viewpager.widget.ViewPager
             android:id="@+id/view_pager"