Bug 1199041 - Clarify comment in DrawableUtil. r=liuche

--HG--
extra : commitid : Gg90aYQD1VS
extra : rebase_source : 2feaed1283dbee169a9ea31bca2bf6b5acec7219

mobile/android/base/util/DrawableUtil.java

@@ -18,8 +18,7 @@ import android.support.v4.graphics.drawable.DrawableCompat;
 public class DrawableUtil {
 
     /**
-     * Tints the given drawable with the given color and returns it. Note that this
-     * transformation does not occur in place on pre-Lollipop devices (bug 1193950).
+     * Tints the given drawable with the given color and returns it.
      */
     @CheckResult
     public static Drawable tintDrawable(@NonNull final Context context, @DrawableRes final int drawableID,
@@ -31,8 +30,10 @@ public class DrawableUtil {
     }
 
     /**
-     * Tints the given drawable with the given tint list and returns it. Note that this
-     * transformation does not occur in place on pre-Lollipop devices (bug 1193950).
+     * Tints the given drawable with the given tint list and returns it. Note that you
+     * should no longer use the argument Drawable because the argument is not mutated
+     * on pre-Lollipop devices but is mutated on L+ due to differences in the Support
+     * Library implementation (bug 1193950).
      */
     @CheckResult
     public static Drawable tintDrawableWithStateList(@NonNull final Drawable drawable,