Update colorPrimary in watch

1. Update colorPrimary in watch. This value is only used for icons and
switch background on watch.

2. Replace hard coded color and disable alpha in switch track.

3. Rename watch_switch_track_mtrl_alpha to be  watch_switch_track_mtrl
since it's no longer a alpha mask.

Change-Id: Ia1eaae62a934c89e3ca6cc8736b256c552f0329b

core/res/res/color/watch_switch_track_color_material.xml

@@ -1,9 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright (C) 2016 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.
@@ -12,10 +15,8 @@
 -->
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:state_enabled="false">
-        <bitmap android:alpha="0.1" android:src="@drawable/watch_switch_track_mtrl_alpha" />
-    </item>
-    <item>
-        <bitmap android:alpha="0.2" android:src="@drawable/watch_switch_track_mtrl_alpha" />
-    </item>
-</selector>
+    <item android:state_enabled="false"
+          android:alpha="?attr/disabledAlpha"
+          android:color="?android:colorPrimary" />
+    <item android:color="?android:colorPrimary" />
+</selector>

core/res/res/layout-watch/preference_widget_switch.xml

@@ -24,7 +24,8 @@
     android:thumb="@drawable/watch_switch_thumb_material_anim"
     android:thumbTint="@color/watch_switch_thumb_color_material"
     android:thumbTintMode="multiply"
-    android:track="@drawable/watch_switch_track_material"
+    android:track="@drawable/watch_switch_track_mtrl"
+    android:trackTint="@color/watch_switch_track_color_material"
     android:focusable="false"
     android:clickable="false"
     android:background="@null" />

core/res/res/values-watch/colors_material.xml

@@ -22,7 +22,7 @@
     <color name="accent_material_dark">#ff5e97f6</color>
     <color name="accent_material_50">#ffd0def7</color>
 
-    <color name="primary_material_dark">#4D4D4D</color>
+    <color name="primary_material_dark">#33ffffff</color>
 
     <color name="button_material_dark">#ff919699</color>
 </resources>