add colortable support to imagegenerator

gyp/images.gyp

 # GYP file for images project.
 {
   'targets': [
     {
       'target_name': 'images',
       'product_name': 'skia_images',
       'type': 'static_library',
       'standalone_static_library': 1,
       'dependencies': [
         'core.gyp:*',
@@ skipping 53 matching lines @@
         '../src/images/SkImageDecoder_libbmp.cpp',
         '../src/images/SkImageDecoder_libgif.cpp',
         '../src/images/SkImageDecoder_libico.cpp',
         '../src/images/SkImageDecoder_libwebp.cpp',
         '../src/images/SkImageDecoder_libjpeg.cpp',
         '../src/images/SkImageDecoder_libpng.cpp',
 
         '../src/images/SkImageEncoder.cpp',
         '../src/images/SkImageEncoder_Factory.cpp',
         '../src/images/SkImageEncoder_argb.cpp',
+        '../src/images/SkImageGenerator.cpp',
         '../src/images/SkImageRef.cpp',
         '../src/images/SkImageRefPool.cpp',
         '../src/images/SkImageRefPool.h',
         '../src/images/SkImageRef_ashmem.h',
         '../src/images/SkImageRef_ashmem.cpp',
         '../src/images/SkImageRef_GlobalPool.cpp',
         '../src/images/SkImages.cpp',
         '../src/images/SkJpegUtility.cpp',
         '../src/images/SkMovie.cpp',
         '../src/images/SkMovie_gif.cpp',
@@ skipping 90 matching lines @@
         }],
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '../include/images',
         ],
       },
     },
   ],
 }