Add luminance mask transfer modes.

gyp/gmslides.gypi

 # include this gypi to include all the golden master slides.
 {
   'sources': [
     '../gm/aaclip.cpp',
     '../gm/aarectmodes.cpp',
     '../gm/alphagradients.cpp',
     '../gm/arcofzorro.cpp',
     '../gm/arithmode.cpp',
     '../gm/bicubicfilter.cpp',
     '../gm/bigmatrix.cpp',
@@ skipping 48 matching lines @@
     '../gm/gradient_matrix.cpp',
     '../gm/gradtext.cpp',
     '../gm/hairlines.cpp',
     '../gm/hairmodes.cpp',
     '../gm/hittestpath.cpp',
     '../gm/imageblur.cpp',
     '../gm/imagemagnifier.cpp',
     '../gm/inversepaths.cpp',
     '../gm/lerpmode.cpp',
     '../gm/lighting.cpp',
+    '../gm/lumamode.cpp',
     '../gm/image.cpp',
     '../gm/imagefiltersbase.cpp',
     '../gm/imagefilterscropped.cpp',
     '../gm/imagefiltersgraph.cpp',
     '../gm/internal_links.cpp',
     '../gm/lcdtext.cpp',
     '../gm/linepaths.cpp',
     '../gm/matrixconvolution.cpp',
     '../gm/megalooper.cpp',
     '../gm/mixedxfermodes.cpp',
@@ skipping 51 matching lines @@
     '../gm/xfermodes2.cpp',
     '../gm/xfermodes3.cpp',
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: