Upstream helper script to build Chromium on iOS and update instructions.

ios/build/tools/convert_gn_xcodeproj.py

Index: ios/build/tools/convert_gn_xcodeproj.py
diff --git a/ios/build/tools/convert_gn_xcodeproj.py b/ios/build/tools/convert_gn_xcodeproj.py
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+++ b/ios/build/tools/convert_gn_xcodeproj.py
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+#!/usr/bin/python
+# Copyright 2016 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.
+
+"""Convert GN Xcode projects to platform and configuration independent targets.
+
+GN generates Xcode projects that build one configuration only. However, typical
+iOS development involves using the Xcode IDE to toggle the platform and
+configuration. This script replaces the 'gn' configuration with 'Debug',
+'Release' and 'Profile', and changes the ninja invokation to honor these
+configurations.
+"""
+
+import argparse
+import collections
+import copy
+import filecmp
+import json
+import hashlib
+import os
+import plistlib
+import random
+import shutil
+import subprocess
+import sys
+import tempfile
+
+
+XCTEST_PRODUCT_TYPE = 'com.apple.product-type.bundle.unit-test'
+
+
+class XcodeProject(object):
+
+  def __init__(self, objects, counter = 0):
+    self.objects = objects
+    self.counter = 0
+
+  def AddObject(self, parent_name, obj):
+    while True:
+      self.counter += 1
+      str_id = "%s %s %d" % (parent_name, obj['isa'], self.counter)
+      new_id = hashlib.sha1(str_id).hexdigest()[:24].upper()
+
+      # Make sure ID is unique. It's possible there could be an id conflict
+      # since this is run after GN runs.
+      if new_id not in self.objects:
+        self.objects[new_id] = obj
+        return new_id
+
+
+def CopyFileIfChanged(source_path, target_path):
+  """Copy |source_path| to |target_path| is different."""
+  target_dir = os.path.dirname(target_path)
+  if not os.path.isdir(target_dir):
+    os.makedirs(target_dir)
+  if not os.path.exists(target_path) or \
+      not filecmp.cmp(source_path, target_path):
+    shutil.copyfile(source_path, target_path)
+
+
+def LoadXcodeProjectAsJSON(path):
+  """Return Xcode project at |path| as a JSON string."""
+  return subprocess.check_output([
+      'plutil', '-convert', 'json', '-o', '-', path])
+
+
+def WriteXcodeProject(output_path, json_string):
+  """Save Xcode project to |output_path| as XML."""
+  with tempfile.NamedTemporaryFile() as temp_file:
+    temp_file.write(json_string)
+    temp_file.flush()
+    subprocess.check_call(['plutil', '-convert', 'xml1', temp_file.name])
+    CopyFileIfChanged(temp_file.name, output_path)
+
+
+def UpdateProductsProject(file_input, file_output, configurations):
+  """Update Xcode project to support multiple configurations.
+
+  Args:
+    file_input: path to the input Xcode project
+    file_output: path to the output file
+    configurations: list of string corresponding to the configurations that
+      need to be supported by the tweaked Xcode projects, must contains at
+      least one value.
+  """
+  json_data = json.loads(LoadXcodeProjectAsJSON(file_input))
+  project = XcodeProject(json_data['objects'])
+
+  objects_to_remove = []
+  for value in project.objects.values():
+    isa = value['isa']
+
+    # TODO(crbug.com/619072): gn does not write the min deployment target in the
+    # generated Xcode project, so add it while doing the conversion, only if it
+    # is not present. Remove this code and comment once the bug is fixed and gn
+    # has rolled past it.
+    if isa == 'XCBuildConfiguration':
+      build_settings = value['buildSettings']
+      if 'IPHONEOS_DEPLOYMENT_TARGET' not in build_settings:
+        build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '9.0'
+
+    # Remove path name key and change path to basename.
+    if isa == 'PBXFileReference':
+      if 'name' in value:
+        del value['name']
+      value['path'] = os.path.basename(value['path'])
+
+    # Teach build shell script to look for the configuration and platform.
+    if isa == 'PBXShellScriptBuildPhase':
+      value['shellScript'] = value['shellScript'].replace(
+          'ninja -C .',
+          'ninja -C "../${CONFIGURATION}${EFFECTIVE_PLATFORM_NAME}"')
+
+    # Configure BUNDLE_LOADER and TEST_HOST for xctest target (assuming that
+    # the host is named "${target}_host") unless gn has already configured
+    # them.
+    if isa == 'PBXNativeTarget' and value['productType'] == XCTEST_PRODUCT_TYPE:
+      configuration_list = project.objects[value['buildConfigurationList']]
+      for config_name in configuration_list['buildConfigurations']:
+        config = project.objects[config_name]
+        if not config['buildSettings'].get('BUNDLE_LOADER'):
+          config['buildSettings']['BUNDLE_LOADER'] = '$(TEST_HOST)'
+          config['buildSettings']['TEST_HOST'] = \
+              '${BUILT_PRODUCTS_DIR}/%(name)s_host.app/%(name)s' % value
+
+    # Add new configuration, using the first one as default.
+    if isa == 'XCConfigurationList':
+      value['defaultConfigurationName'] = configurations[0]
+      objects_to_remove.extend(value['buildConfigurations'])
+
+      build_config_template = project.objects[value['buildConfigurations'][0]]
+      build_config_template['buildSettings']['CONFIGURATION_BUILD_DIR'] = \
+          '../$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)'
+
+      value['buildConfigurations'] = []
+      for configuration in configurations:
+        new_build_config = copy.copy(build_config_template)
+        new_build_config['name'] = configuration
+        value['buildConfigurations'].append(
+            project.AddObject('products', new_build_config))
+
+  for object_id in objects_to_remove:
+    del project.objects[object_id]
+
+  objects = collections.OrderedDict(sorted(project.objects.iteritems()))
+  WriteXcodeProject(file_output, json.dumps(json_data))
+
+
+def ConvertGnXcodeProject(input_dir, output_dir, configurations):
+  '''Tweak the Xcode project generated by gn to support multiple configurations.
+
+  The Xcode projects generated by "gn gen --ide" only supports a single
+  platform and configuration (as the platform and configuration are set
+  per output directory). This method takes as input such projects and
+  add support for multiple configurations and platforms (to allow devs
+  to select them in Xcode).
+
+  Args:
+    input_dir: directory containing the XCode projects created by "gn gen --ide"
+    output_dir: directory where the tweaked Xcode projects will be saved
+    configurations: list of string corresponding to the configurations that
+      need to be supported by the tweaked Xcode projects, must contains at
+      least one value.
+  '''
+  # Update products project.
+  products = os.path.join('products.xcodeproj', 'project.pbxproj')
+  product_input = os.path.join(input_dir, products)
+  product_output = os.path.join(output_dir, products)
+  UpdateProductsProject(product_input, product_output, configurations)
+
+  # Copy sources project and all workspace.
+  sources = os.path.join('sources.xcodeproj', 'project.pbxproj')
+  CopyFileIfChanged(os.path.join(input_dir, sources),
+                    os.path.join(output_dir, sources))
+  xcwspace = os.path.join('all.xcworkspace', 'contents.xcworkspacedata')
+  CopyFileIfChanged(os.path.join(input_dir, xcwspace),
+                    os.path.join(output_dir, xcwspace))
+
+
+def Main(args):
+  parser = argparse.ArgumentParser(
+      description='Convert GN Xcode projects for iOS.')
+  parser.add_argument(
+      'input',
+      help='directory containing [product|sources|all] Xcode projects.')
+  parser.add_argument(
+      'output',
+      help='directory where to generate the iOS configuration.')
+  parser.add_argument(
+      '--add-config', dest='configurations', default=[], action='append',
+      help='configuration to add to the Xcode project')
+  args = parser.parse_args(args)
+
+  if not os.path.isdir(args.input):
+    sys.stderr.write('Input directory does not exists.\n')
+    return 1
+
+  required = set(['products.xcodeproj', 'sources.xcodeproj', 'all.xcworkspace'])
+  if not required.issubset(os.listdir(args.input)):
+    sys.stderr.write(
+        'Input directory does not contain all necessary Xcode projects.\n')
+    return 1
+
+  if not args.configurations:
+    sys.stderr.write('At least one configuration required, see --add-config.\n')
+    return 1
+
+  ConvertGnXcodeProject(args.input, args.output, args.configurations)
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))
+
+