SystemUI: Enable fading squiggle animation of qs media player

- fixes the line having different curves between played and unplayed section
- before https://imgur.com/a/vn4smvb
- after https://imgur.com/a/7rL4jV6

Change-Id: I2d2522c66341662eff74eb7d3686be7aa6e7ac5c

packages/SystemUI/src/com/android/systemui/media/controls/ui/binder/SeekBarObserver.kt

@@ -119,7 +119,8 @@ open class SeekBarObserver(private val holder: MediaViewHolder) :
         holder.seekBar.isEnabled = data.seekAvailable
         progressDrawable?.animate =
             data.playing && !data.scrubbing && animationEnabled && data.listening
-        progressDrawable?.transitionEnabled = !data.seekAvailable
+        progressDrawable?.minWaveEndpoint = if (data.seekAvailable) 0f else 0.2f
+        progressDrawable?.matchedWaveEndpoint = if (data.seekAvailable) 1f else 0.6f
 
         if (holder.seekBar.maxHeight != seekBarEnabledMaxHeight) {
             holder.seekBar.maxHeight = seekBarEnabledMaxHeight

packages/SystemUI/src/com/android/systemui/media/controls/ui/drawable/SquigglyProgress.kt

@@ -53,11 +53,11 @@ class SquigglyProgress : Drawable() {
     private var lastFrameTime = -1L
 
     /* distance over which amplitude drops to zero, measured in wavelengths */
-    private val transitionPeriods = 1.5f
+    var transitionPeriods = 1.5f
     /* wave endpoint as percentage of bar when play position is zero */
-    private val minWaveEndpoint = 0.2f
+    var minWaveEndpoint = 0.2f
     /* wave endpoint as percentage of bar when play position matches wave endpoint */
-    private val matchedWaveEndpoint = 0.6f
+    var matchedWaveEndpoint = 0.6f
 
     // Horizontal length of the sine wave
     var waveLength = 0f