LightingShader and NormalSource comment and style fixes

src/core/SkNormalSource.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkNormalSource_DEFINED
 #define SkNormalSource_DEFINED
 
@@ skipping 50 matching lines @@
         is retrieved by:
             N.x = R-127;
             N.y = G-127;
             N.z = B-127;
             N.normalize();
         The +Z axis is thus encoded in RGB as (127, 127, 255) while the -Z axis is
         (127, 127, 0).
     */
     static sk_sp<SkNormalSource> MakeFromNormalMap(sk_sp<SkShader> map, const SkMatrix& ctm);
 
-    /** Returns a normal source that provides straight-up normals only (0, 0, 1).
+    /** Returns a normal source that provides straight-up normals only <0, 0, 1>.
     */
     static sk_sp<SkNormalSource> MakeFlat();
 
     /** This enum specifies the shape of the bevel. All bevels output <0, 0, 1> as the surface
      *  normal for any point more than 'width' away from any edge.
      *
      *  Mathematical details:
      *  For the purpose of describing the shape of the bevel, we define 'w' to be the given width of
      *  the bevel, and 'h' to be the given height. We will assume the shape is rotated such that the
      *  point being shaded as well as the closest point in the shape's edge to that point are in the
@@ skipping 19 matching lines @@
         /* This bevel simulates a surface that sharply becomes perpendicular to the x-y plane when
          * at 'width' units from the nearest edge, and then rounds off towards the shape's
          * edge, smoothly becoming parallel to the x-y plane.
          *
          * Mathematical details:
          * This bevel follows the only quadratic bezier curve whose start point is at (w, 0, 0),
          * control point is at (0, 0, 0), and end point is at (0, 0, h).
          */
         kRoundedIn
     };
-    /** Returns a normal source that generates a bevel for the given shape. UNIMPLEMENTED: Will
-        return straight-up normals only.
+
+    /** Returns a normal source that generates a bevel for the shape being drawn. Currently this is
+        not implemented on CPU rendering. On GPU this currently only works for anti-aliased circles
+        and rectangles.
 
         @param  type   the type of bevel to add.
         @param  width  the width of the bevel, in source space. Must be positive.
         @param  height the height of the plateau, in source space. Can be positive, negative,
                        or zero. A negative height means the simulated bevels slope downwards.
     */
     static sk_sp<SkNormalSource> MakeBevel(BevelType, SkScalar width, SkScalar height);
 
     SK_DEFINE_FLATTENABLE_TYPE(SkNormalSource)
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
 };
 
 #endif