Add GM to test non-AA pixel snapping for points, lines, rects.

gyp/gmslides.gypi

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 # include this gypi to include all the golden master slides.
 {
   'include_dirs': [
     '../gm',
     # include dirs needed by particular GMs
     '../src/utils/debugger',
@@ skipping 155 matching lines @@
         '../gm/pathinterior.cpp',
         '../gm/pathopsinverse.cpp',
         '../gm/pathopsskpclip.cpp',
         '../gm/pathreverse.cpp',
         '../gm/peekpixels.cpp',
         '../gm/perlinnoise.cpp',
         '../gm/picture.cpp',
         '../gm/pictureimagefilter.cpp',
         '../gm/pictureshader.cpp',
         '../gm/pictureshadertile.cpp',
+        '../gm/pixelsnap.cpp',
         '../gm/points.cpp',
         '../gm/poly2poly.cpp',
         '../gm/polygons.cpp',
         '../gm/quadpaths.cpp',
         '../gm/recordopts.cpp',
         '../gm/rects.cpp',
         '../gm/repeated_bitmap.cpp',
         '../gm/resizeimagefilter.cpp',
         '../gm/rrect.cpp',
         '../gm/rrects.cpp',
@@ skipping 88 matching lines @@
         '../gm/shadertext2.cpp',
         '../gm/shadertext3.cpp',
 
         # TODO(reed): Allocates more memory than Android devices are capable of
         # fulfilling. See http://skbug.com/1978
         '../gm/verylargebitmap.cpp',
       ],
     }],
   ],
 }