remove redundant/deprecated TwoPointRadial gradiet -- use TwoPointConical

This CL derived from https://codereview.chromium.org/1114243005/

BUG=skia:

Review URL: https://codereview.chromium.org/1117423003
diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index 91d431f..4c4dba3 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -246,19 +246,6 @@
                             //   to (0,0) as bitmap x coord, where angle = 0 is
                             //   bitmap left edge of bitmap = 2pi is the
                             //   right edge. Bitmap is 1 pixel tall. No extras
-        kTwoPointRadial_BitmapType,
-                            //<! Matrix transforms to space where (0,0) is
-                            //   the center of the starting circle.  The second
-                            //   circle will be centered (x, 0) where x  may be
-                            //   0. The post-matrix space is normalized such
-                            //   that 1 is the second radius - first radius.
-                            //   Three extra parameters are returned:
-                            //      0: x-offset of second circle center
-                            //         to first.
-                            //      1: radius of first circle in post-matrix
-                            //         space
-                            //      2: the second radius minus the first radius
-                            //         in pre-transformed space.
         kTwoPointConical_BitmapType,
                             //<! Matrix transforms to space where (0,0) is
                             //   the center of the starting circle.  The second
@@ -314,7 +301,7 @@
      *      fPoint[0] and fPoint[1] are the end-points of the gradient
      *  Radial:
      *      fPoint[0] and fRadius[0] are the center and radius
-     *  Radial2:
+     *  Conical:
      *      fPoint[0] and fRadius[0] are the center and radius of the 1st circle
      *      fPoint[1] and fRadius[1] are the center and radius of the 2nd circle
      *  Sweep:
@@ -326,7 +313,6 @@
         kColor_GradientType,
         kLinear_GradientType,
         kRadial_GradientType,
-        kRadial2_GradientType,
         kSweep_GradientType,
         kConical_GradientType,
         kLast_GradientType = kConical_GradientType