Proguard changing methods required for click feedback aniamtion

Bug: 18323452
Change-Id: Iac6d75a3c46c3a4c2a74af43bd1fca738235c2d5
diff --git a/proguard.flags b/proguard.flags
index 0b28c0e..83a491d 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -57,3 +57,8 @@
   public float getAnimationProgress();
   public void setAnimationProgress(float);
 }
+
+-keep class com.android.launcher3.FastBitmapDrawable {
+  public int getBrightness();
+  public void setBrightness(int);
+}