[Fingerprint] Use accent color for fingerprint highlight

Set the fingerprint activated color, while registering a new
fingerprint to be 50% alpha of the accent color. This allows the
color to be changed with the theme, so that it will be highlighted
blue during setup wizard.

Bug: 21695577
Change-Id: Iee68506a4fbb8e8996bdb52694992ac460ae943d

res/color/fingerprint_indicator_background_activated.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright (C) 2015 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.
+-->
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:alpha="0.5" android:color="?android:attr/colorAccent" />
+</selector>

res/values/colors.xml

@@ -67,7 +67,6 @@
     <color name="fingerprint_progress_ring">?android:attr/colorAccent</color>
     <color name="fingerprint_progress_ring_bg">#20000000</color>
     <color name="fingerprint_indicator_background_resting">#12000000</color>
-    <color name="fingerprint_indicator_background_activated">#80009688</color>
 
     <color name="running_processes_system_ram">#ff384248</color>
     <color name="running_processes_apps_ram">#ff009587</color>