Fix ChromeOS build broken in f84722e4777

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 144 matching lines @@
           ],
         },{ #else if skia_os != android
           'sources!': [
             '../src/images/SkImageRef_ashmem.h',
             '../src/images/SkImageRef_ashmem.cpp',
           ],
         }],
         [ 'skia_os == "chromeos"', {
           'dependencies': [
              'chromeos_deps.gyp:gif',
+             'libpng.gyp:libpng',

[scroggo, 2014/02/24 20:52:52]

Should this go into chromeos_deps?

I think it's fine to check this in to get everything building, even if it's not
the best way to do it (which it may be).

[hal.canary, 2014/02/24 21:05:10]

I don't think so, since there is no special handling of libpng in DEPS, like
there is for giflib.

           ],
         }],
         [ 'skia_os == "ios"', {
            'include_dirs': [
              '../include/utils/mac',
            ],
         }],
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '../include/images',
         ],
       },
     },
   ],
 }