Replace uses of GR_DEBUG by SK_DEBUG.

gyp/common.gypi

 # Copyright 2011 The Android Open Source Project
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # This file is automatically included by gyp_skia when building any target.
 
 {
   'includes': [
     'common_variables.gypi',
@@ skipping 74 matching lines @@
           'defines': [
             'SK_USE_CDB',
           ],
         },
       ],
     ],
     'configurations': {
       'Debug': {
         'defines': [
           'SK_DEBUG',
-          'GR_DEBUG=1',
           'SK_DEVELOPER=1',
         ],
       },
       'Release': {
         'defines': [
           'SK_RELEASE',
           'GR_RELEASE=1',
         ],
       },
       'Release_Developer': {
         'inherit_from': ['Release'],
         'defines': [
           'SK_DEVELOPER=1',
         ],
       },
     },
   }, # end 'target_defaults'
 }
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: