Update Shader.TileMode documentation.

Updated documentation for TileModel.DECAL to indicate that
"original domain" refers to the bounds of the shader and
transparent black will be drawn for regions outsdie of the
shader.

Fixes: 169331275
Test: N/A
Change-Id: I6afdf4354668197cd7f584071fc35f80e07053fe

graphics/java/android/graphics/Shader.java

@@ -83,21 +83,22 @@ public class Shader {
 
     public enum TileMode {
         /**
-         * replicate the edge color if the shader draws outside of its
-         * original bounds
+         * Replicate the edge color if the shader draws outside of its
+         * original bounds.
          */
         CLAMP   (0),
         /**
-         * repeat the shader's image horizontally and vertically
+         * Repeat the shader's image horizontally and vertically.
          */
         REPEAT  (1),
         /**
-         * repeat the shader's image horizontally and vertically, alternating
-         * mirror images so that adjacent images always seam
+         * Repeat the shader's image horizontally and vertically, alternating
+         * mirror images so that adjacent images always seam.
          */
         MIRROR(2),
         /**
-         * Only draw within the original domain, return transparent-black everywhere else
+         * Render the shader's image pixels only within its original bounds. If the shader
+         * draws outside of its original bounds, transparent black is drawn instead.
          */
         DECAL(3);