First pass at a meta-build wrapper for the gyp->gn migration

build/mb_conf.pyl

+# Copyright 2015 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.
+
+{
+  'build_configs': {
+    'gn_debug_shared':    None,
+    'gn_release_static':  None,
+    'gyp':                ['gyp'],
+    'gyp_debug_bot':      ['gyp_shared', 'bot'],
+    'gyp_release_bot':    ['gyp_static', 'bot'],
+    'gyp_release_trybot': ['gyp_static', 'trybot'],
+    'gyp_shared':         None,
+    'gyp_static':         None,
+  },
+
+  'mixins': {
+    'bot': {
+      'mixins': ['minimal_symbols']
+    },
+
+    'dcheck_always_on': {
+      'gn_args': ['dcheck_always_on=true'],
+      'gyp_defines': ['dcheck_always_on=1'],
+    },
+
+    'debug': {
+      'gn_args': ['is_debug=true'], 
+      'gyp_defines': [],
+      'gyp_configs': ['Debug', 'Debug_x64'],
+    },
+
+    'gn': {
+      'type': 'gn',
+    },
+
+    'gyp': {
+      'type': 'gyp',
+    },
+
+    'gyp_chromium': {
+      'type': 'gyp_one_config',
+    },
+
+    'minimal_symbols': {
+      'gn_args': ['symbol_level=1'],
+      'gyp_defines': ['fastbuild=1'],
+    },
+
+    'release': {
+      'gn_args': ['is_debug=false'],
+      'gyp_defines': [],
+      'gyp_configs': ['Release', 'Release_x64']
+    },
+
+    'shared': {
+      'gn_args': ['is_component_build=true'],
+      'gyp_defines': ['component=shared_library'],
+    },
+
+    'static': {
+      'gn_args': ['is_component_build=false'],
+      'gyp_defines': ['component=static_library'],
+    },
+
+    'trybot': {
+      'mixins': ['bot', 'dcheck_always_on'],
+    },
+  },
+}