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

With these changes, the ios trybots should start working.

Part of this change makes MB aware of the bot config files
in //ios/build/bots, so that we don't have to configure
the iOS bots in two different places.

See the updated MB docs for details.

R=smut@google.com, sdefresne@chromium.org, stuartmorgan@chromium.org
BUG=517216

Review URL: https://codereview.chromium.org/1411183010

Cr-Commit-Position: refs/heads/master@{#360688}

ios/build/bots/chromium.mac/iOS_Device_GN.json

@@ -0,0 +1,25 @@
+{
+  "owners": [
+    "dpranke",
+    "smut"
+  ],
+  "comments": [
+    "GN + Ninja fat binary builder."
+  ],
+  "xcode version": "7.0",
+  "GYP_DEFINES": {
+    "chromium_ios_signing": "0",
+    "target_subarch": "both"
+  },
+  "gn_args": [
+    "ios_enable_code_signing=false",
+    "target_cpu=\"arm\"",
+    "target_os=\"ios\""
+  ],
+  "mb_type": "gn",
+  "compiler": "ninja",
+  "configuration": "Release",
+  "sdk": "iphoneos9.0",
+  "tests": [
+  ]
+}

ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json

@@ -0,0 +1,23 @@
+{
+  "owners": [
+    "dpranke",
+    "smut"
+  ],
+  "comments": [
+    "GN + Ninja simulator build."
+  ],
+  "xcode version": "7.0",
+  "GYP_DEFINES": {
+    "chromium_ios_signing": "0",
+    "target_subarch": "both"
+  },
+  "gn_args": [
+    "target_os=\"ios\""
+  ],
+  "mb_type": "gn",
+  "compiler": "ninja",
+  "configuration": "Debug",
+  "sdk": "iphonesimulator9.0",
+  "tests": [
+  ]
+}

ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json

@@ -0,0 +1,23 @@
+{
+  "owners": [
+    "dpranke",
+    "smut"
+  ],
+  "comments": [
+    "GN + Ninja simulator build."
+  ],
+  "xcode version": "7.0",
+  "GYP_DEFINES": {
+    "chromium_ios_signing": "0",
+    "target_subarch": "both"
+  },
+  "gn_args": [
+    "target_os=\"ios\""
+  ],
+  "mb_type": "gn",
+  "compiler": "ninja",
+  "configuration": "Debug",
+  "sdk": "iphonesimulator9.0",
+  "tests": [
+  ]
+}

ios/build/bots/tryserver.chromium.mac/ios_rel_device_gn.json

@@ -0,0 +1,25 @@
+{
+  "owners": [
+    "dpranke",
+    "smut"
+  ],
+  "comments": [
+    "GN + Ninja fat binary builder."
+  ],
+  "xcode version": "7.0",
+  "GYP_DEFINES": {
+    "chromium_ios_signing": "0",
+    "target_subarch": "both"
+  },
+  "gn_args": [
+    "ios_enable_code_signing=false",
+    "target_cpu=\"arm\"",
+    "target_os=\"ios\""
+  ],
+  "mb_type": "gn",
+  "compiler": "ninja",
+  "configuration": "Release",
+  "sdk": "iphoneos9.0",
+  "tests": [
+  ]
+}

tools/mb/docs/design_spec.md

@@ -38,9 +38,18 @@ It is structured as a single binary that supports a list of subcommands:
 
 ### Configurations
 
-`mb` looks in the `//tools/mb/mb_config.pyl` config file to determine whether
-to use GYP or GN for a particular build directory, and what set of flags
-(`GYP_DEFINES` or `gn args`) to use.
+`mb` will first look for a bot config file in a set of different locations
+(initially just in //ios/build/bots). Bot config files are JSON files that
+contain keys for 'GYP_DEFINES' (a list of strings that will be joined together
+with spaces and passed to GYP, or a dict that will be similarly converted),
+'gn_args' (a list of strings that will be joined together), and an
+'mb_type' field that says whether to use GN or GYP. Bot config files
+require the full list of settings to be given explicitly.
+
+If no mathcing bot config file is found, `mb` looks in the
+`//tools/mb/mb_config.pyl` config file to determine whether to use GYP or GN
+for a particular build directory, and what set of flags (`GYP_DEFINES` or `gn
+args`) to use.
 
 A config can either be specified directly (useful for testing) or by specifying
 the master name and builder name (useful on the bots so that they do not need

tools/mb/docs/user_guide.md

@@ -107,9 +107,11 @@ a directory, then runs GYP or GN as appropriate:
 Either the `-c/--config` flag or the `-m/--master` and `-b/--builder` flags
 must be specified so that `mb` can figure out which config to use.
 
-By default, MB will look in `//tools/mb/mb_config.pyl` to look up the config
-information, but you can specify a custom config file using the
-`-f/--config-file` flag.
+By default, MB will look for a bot config file under `//ios/build/bots` (see
+[design_spec.md](the design spec) for details of how the bot config files
+work). If no matching one is found, will then look in
+`//tools/mb/mb_config.pyl` to look up the config information, but you can
+specify a custom config file using the `-f/--config-file` flag.
 
 The path must be a GN-style "source-absolute" path (as above).
 

tools/mb/mb.py

@@ -344,13 +344,15 @@ def GNValsFromDir(self, build_dir):
     }
 
   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.
@@ -360,6 +362,28 @@ def Lookup(self):
 
     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)