Voicemail ui indicates both time left and playback speed.

- Playback time indicator has changed from current position in
  voicemail to time remaining.
- This same text view is also used to briefly display current playback
  rate when playback rate buttons are pressed.
- Unit tests to show that this logic works.
- This cl introduces a new class whose job is to handle the transition
  between the different text states.
- Fixes a crash when we might release the player before the last
  update gets the duration from the released player.
- New test method to fetch a text view's content on the ui thread.

Bug: 5044075
Change-Id: Ie3cf6e58c1a0139edb78cf3564a8aec94512156f
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 5ff5662..4069c49 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -1645,6 +1645,17 @@
    server directly to listen to the voicemails. [CHAR LIMIT=20] -->
     <string name="voicemail_status_action_call_server">Call voicemail</string>
 
+    <!-- The slowest voicemail playback speed. [CHAR LIMIT=30] -->
+    <string name="voicemail_speed_slowest">slowest speed</string>
+    <!-- Slower than normal voicemail playback speed. [CHAR LIMIT=30] -->
+    <string name="voicemail_speed_slower">slow speed</string>
+    <!--  Normal voicemail playback speed. [CHAR LIMIT=30] -->
+    <string name="voicemail_speed_normal">normal speed</string>
+    <!--  Faster than normal pvoicemail playback speed. [CHAR LIMIT=30] -->
+    <string name="voicemail_speed_faster">fast speed</string>
+    <!--  Fastest voicemail playback speed. [CHAR LIMIT=30] -->
+    <string name="voicemail_speed_fastest">fastest speed</string>
+
     <!-- The counter for calls in a group in the call log [CHAR LIMIT=5] -->
     <string name="call_log_item_count">(%1$d)</string>