Adds feedback to Home and Back tutorials.

Back feedback:
 - Too far from edge of screen
 - Cancelled (reversed gesture, swiped upwards, etc.)
 - Inside nav bar region
 - Demo: https://drive.google.com/open?id=1pc_hr7i-iZmgF37CN8oijPjhOvvsJoEG

Home feedback:
 - Too far from edge of screen
 - Paused too long (Overview detected)
 - Swiped sideways instead of up
 - Demo: https://drive.google.com/open?id=1NGYAlqV2wJtM2DOJ1pZM-r8N1SYVtMos

Bug: 148542211
Test: Manual
Change-Id: I627ed7c6e9b005d35794e4ae568529b5613cbf70
diff --git a/quickstep/res/values/styles.xml b/quickstep/res/values/styles.xml
index 4915f5f..3926988 100644
--- a/quickstep/res/values/styles.xml
+++ b/quickstep/res/values/styles.xml
@@ -47,6 +47,14 @@
         <item name="android:textSize">21sp</item>
     </style>
 
+    <style name="TextAppearance.GestureTutorial.Feedback"
+        parent="TextAppearance.GestureTutorial">
+        <item name="android:gravity">center</item>
+        <item name="android:textColor">@color/gesture_tutorial_feedback_color</item>
+        <item name="android:letterSpacing">0.03</item>
+        <item name="android:textSize">21sp</item>
+    </style>
+
     <style name="TextAppearance.GestureTutorial.ButtonLabel"
         parent="TextAppearance.GestureTutorial.CallToAction">
         <item name="android:gravity">center</item>