skia: Fix command buffer support on the mac

gyp/common_conditions.gypi

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # conditions used in both common.gypi and skia.gyp in chromium
 #
 {
   'defines': [
     'SK_ALLOW_STATIC_GLOBAL_INITIALIZERS=<(skia_static_initializers)',
@@ skipping 599 matching lines @@
         ],
       },
     ],
 
     [ 'skia_moz2d', {
       'defines': [
         # add flags here (e.g. SK_SUPPORT_LEGACY_...) needed by moz2d
       ],
     }],
 
-    [ 'skia_command_buffer', {
+    [ 'skia_command_buffer and skia_os == "linux"', {
       'ldflags': [
           '-Wl,-rpath,\$$ORIGIN/lib',
       ],
     }],
 
+    [ 'skia_command_buffer and skia_os == "mac"', {
+      'xcode_settings': {
+          'LD_RUNPATH_SEARCH_PATHS': ['@executable_path/.'],
+      },
+    }],
+
   ], # end 'conditions'
   # The Xcode SYMROOT must be at the root. See build/common.gypi in chromium for more details
   'xcode_settings': {
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }