Improve Skia configuration.

skia/skia_common.gypi

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This gypi file handles the removal of platform-specific files from the
 # Skia build.
 {
+  'include_dirs': [
+    '..',
+    'config',
+  ],
+
   'conditions': [
     [ 'OS != "android"', {
       'sources/': [
          ['exclude', '_android\\.(cc|cpp)$'],
       ],
     }],
     [ 'OS != "ios"', {
       'sources/': [
          ['exclude', '_ios\\.(cc|cpp|mm?)$'],
       ],
     }],
     [ 'OS != "mac"', {
       'sources/': [
         ['exclude', '_mac\\.(cc|cpp|mm?)$'],
       ],
     }],
     [ 'OS != "win"', {
       'sources/': [ ['exclude', '_win\\.(cc|cpp)$'] ],
     }],
     [ 'use_glib == 0', {
       'sources/': [ ['exclude', '_linux\\.(cc|cpp)$'] ],
     }],
   ],
 
+  'variables': {
+    'variables': { 'conditions': [
+      [ 'OS == "win"', {
+        'skia_atomics_impl': 'win',
+        'skia_mutex_impl': 'win',
+      }, { 'conditions': [
+        [ 'OS == "android" and use_system_skia == 1', {
+          'skia_atomics_impl': 'android',
+          'skia_mutex_impl': 'pthread',
+        }, {
+          'skia_atomics_impl': 'sync',
+          'skia_mutex_impl': 'pthread',
+        }],
+      ]}],
+    ]},
+    'skia_threading_defines': [
+      'SK_ATOMICS_PLATFORM_H="third_party/skia/src/ports/SkAtomics_<(skia_atomics_impl).h"',
+      'SK_MUTEX_PLATFORM_H="third_party/skia/src/ports/SkMutex_<(skia_mutex_impl).h"',
+    ],
+  },
+
+  'defines': [
+    '<@(skia_threading_defines)',
+  ],
+
+  'direct_dependent_settings': {
+    'include_dirs': [
+      '..',
+      'config',
+    ],
+    'defines': [
+      '<@(skia_threading_defines)',

[djsollen, 2013/09/27 18:17:10]

should this be in an all_dependent_settings block so that if chrome references
those values nothing breaks?

[bungeman-skia, 2013/09/27 18:39:43]

Good question with a complex answer. So, as a policy thing, if a target has
sources which include Skia headers, it should be directly depending on Skia. If
it has (public) headers which include Skia headers, then it needs to
'export_dependent_settings'. So I would argue that the answer to this is 'no'

Note that in skia_library.gyp the defines in the skia_export_defines variable
are also in a 'direct_dependent_settings' block. If we change this we would also
need to change that, since we certainly don't want to be able to include headers
and have a different set of defines.

+    ],
+  },
+
   'msvs_disabled_warnings': [4244, 4267, 4341, 4345, 4390, 4554, 4748, 4800],
 }