Make MB aware of iOS bot configs and get iOS working.

tools/mb/mb.py

 #!/usr/bin/env python
 # 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.
 
 """MB - the Meta-Build wrapper around GYP and GN
 
 MB is a wrapper script for GYP and GN that can be used to generate build files
 for sets of canned configurations and analyze them.
 """
@@ skipping 326 matching lines @@
       name = fields[0]
       val = ' '.join(fields[2:])
       gn_args.append('%s=%s' % (name, val))
 
     return {
       'gn_args': ' '.join(gn_args),
       'type': 'gn',
     }
 
   def Lookup(self):
-    self.ReadConfigFile()
-    config = self.ConfigFromArgs()
-    if not config in self.configs:
-      raise MBErr('Config "%s" not found in %s' %
-                  (config, self.args.config_file))
+    vals = self.ReadBotConfig()
+    if not vals:
+      self.ReadConfigFile()
+      config = self.ConfigFromArgs()
+      if not config in self.configs:
+        raise MBErr('Config "%s" not found in %s' %
+                    (config, self.args.config_file))
 
-    vals = self.FlattenConfig(config)
+      vals = self.FlattenConfig(config)
 
     # Do some basic sanity checking on the config so that we
     # don't have to do this in every caller.
     assert 'type' in vals, 'No meta-build type specified in the config'
     assert vals['type'] in ('gn', 'gyp'), (
         'Unknown meta-build type "%s"' % vals['gn_args'])
 
     return vals
 
+  def ReadBotConfig(self):
+    if not self.args.master or not self.args.builder:
+      return {}
+    path = self.PathJoin(self.chromium_src_dir, 'ios', 'build', 'bots',
+                         self.args.master, self.args.builder + '.json')
+    if not self.Exists(path):
+      return {}
+
+    contents = json.loads(self.ReadFile(path))
+    gyp_vals = contents.get('GYP_DEFINES', {})
+    if isinstance(gyp_vals, dict):
+      gyp_defines = ' '.join('%s=%s' % (k, v) for k, v in gyp_vals.items())
+    else:
+      gyp_defines = ' '.join(gyp_vals)
+    gn_args = ' '.join(contents.get('gn_args', []))
+
+    return {
+        'type': contents.get('mb_type', ''),
+        'gn_args': gn_args,
+        'gyp_defines': gyp_defines,
+    }
+
   def ReadConfigFile(self):
     if not self.Exists(self.args.config_file):
       raise MBErr('config file not found at %s' % self.args.config_file)
 
     try:
       contents = ast.literal_eval(self.ReadFile(self.args.config_file))
     except SyntaxError as e:
       raise MBErr('Failed to parse config file "%s": %s' %
                  (self.args.config_file, e))
 
@@ skipping 717 matching lines @@
 
 if __name__ == '__main__':
   try:
     sys.exit(main(sys.argv[1:]))
   except MBErr as e:
     print(e)
     sys.exit(1)
   except KeyboardInterrupt:
     print("interrupted, exiting", stream=sys.stderr)
     sys.exit(130)