Delete ChromeOS code

gyp/codec.gyp

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # GYP file for codec project.
@@ skipping 117 matching lines @@
           'defines': [
             'qDNGBigEndian=0',
           ],
         }],
         ['skia_os == "ios" or skia_os == "mac"', {
           'xcode_settings': {
             'OTHER_CFLAGS': ['-fexceptions'],
             'OTHER_CPLUSPLUSFLAGS': ['-fexceptions'],
           },
         }],
-        ['skia_os == "chromeos"', {
-          'link_settings': {
-            'libraries': ['-lrt', ],
-          },
-        }],
       ],
     },
   ],
 }