Write out useful Android GN vars in a non-gradle-specific form.

build/android/gradle/generate_gradle.py

 #!/usr/bin/env 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.
 
 """Generates an Android Studio project from a GN target."""
 
 import argparse
 import codecs
 import logging
@@ skipping 59 matching lines @@
 def _WriteFile(path, data):
   """Writes |data| to |path|, constucting parent directories if necessary."""
   logging.info('Writing %s', path)
   dirname = os.path.dirname(path)
   if not os.path.exists(dirname):
     os.makedirs(dirname)
   with codecs.open(path, 'w', 'utf-8') as output_file:
     output_file.write(data)
 
 
+def _ReadBuildVars(output_dir):
+  with open(os.path.join(output_dir, 'build_vars.txt')) as f:
+    return dict(l.rstrip().split('=', 1) for l in f)
+
+
 def _RunNinja(output_dir, args):
   cmd = ['ninja', '-C', output_dir, '-j50']
   cmd.extend(args)
   logging.info('Running: %r', cmd)
   subprocess.check_call(cmd)
 
 
 def _QueryForAllGnTargets(output_dir):
   # Query ninja rather than GN since it's faster.
   cmd = ['ninja', '-C', output_dir, '-t', 'targets']
@@ skipping 137 matching lines @@
 
 
 def _GenerateLocalProperties(sdk_dir):
   """Returns the data for project.properties as a string."""
   return '\n'.join([
       '# Generated by //build/android/gradle/generate_gradle.py',
       'sdk.dir=%s' % sdk_dir,
       ''])
 
 
-def _GenerateGradleFile(build_config, config_json, java_dirs, relativize,
+def _GenerateGradleFile(build_config, build_vars, java_dirs, relativize,
                         use_gradle_process_resources, jinja_processor):
   """Returns the data for a project's build.gradle."""
   deps_info = build_config['deps_info']
   gradle = build_config['gradle']
 
   if deps_info['type'] == 'android_apk':
     target_type = 'android_apk'
   elif deps_info['type'] == 'java_library' and not deps_info['is_prebuilt']:
     if deps_info['requires_android']:
       target_type = 'android_library'
     else:
       target_type = 'java_library'
   else:
     return None
 
   variables = {}
   variables['template_type'] = target_type
   variables['use_gradle_process_resources'] = use_gradle_process_resources
-  variables['build_tools_version'] = config_json['build_tools_version']
-  variables['compile_sdk_version'] = config_json['compile_sdk_version']
+  variables['build_tools_version'] = (
+      build_vars['android_sdk_build_tools_version'])
+  variables['compile_sdk_version'] = build_vars['android_sdk_version']
   android_manifest = gradle.get('android_manifest',
                                 _DEFAULT_ANDROID_MANIFEST_PATH)
   variables['android_manifest'] = relativize(android_manifest)
   variables['java_dirs'] = relativize(java_dirs)
   variables['prebuilts'] = relativize(gradle['dependent_prebuilt_jars'])
   deps = [_ProjectEntry.FromBuildConfigPath(p)
           for p in gradle['dependent_android_projects']]
 
   variables['android_project_deps'] = [d.ProjectName() for d in deps]
   deps = [_ProjectEntry.FromBuildConfigPath(p)
@@ skipping 111 matching lines @@
   # There are many unused libraries, so restrict to those that are actually used
   # when using --all.
   if args.all:
     main_entries = [e for e in main_entries if e.GetType() == 'android_apk']
 
   all_entries = _FindAllProjectEntries(main_entries)
   logging.info('Found %d dependent build_config targets.', len(all_entries))
 
   logging.warning('Writing .gradle files...')
   jinja_processor = jinja_template.JinjaProcessor(host_paths.DIR_SOURCE_ROOT)
-  config_json = build_utils.ReadJson(
-      os.path.join(output_dir, 'gradle', 'config.json'))
+  build_vars = _ReadBuildVars(output_dir)
   project_entries = []
   srcjar_tuples = []
   for entry in all_entries:
     if entry.GetType() not in ('android_apk', 'java_library'):
       continue
 
     entry_output_dir = os.path.join(gradle_output_dir, entry.GradleSubdir())
     relativize = lambda x, d=entry_output_dir: _RebasePath(x, d)
     build_config = entry.BuildConfig()
 
     srcjars = _RebasePath(build_config['gradle'].get('bundled_srcjars', []))
     if not args.use_gradle_process_resources:
       srcjars += _RebasePath(build_config['javac']['srcjars'])
 
     java_sources_file = build_config['gradle'].get('java_sources_file')
     if java_sources_file:
       java_sources_file = _RebasePath(java_sources_file)
 
     java_dirs = _CreateJavaSourceDir(output_dir, entry_output_dir,
                                      java_sources_file)
     if srcjars:
       java_dirs.append(os.path.join(entry_output_dir, _SRCJARS_SUBDIR))
 
-    data = _GenerateGradleFile(build_config, config_json, java_dirs, relativize,
+    data = _GenerateGradleFile(build_config, build_vars, java_dirs, relativize,
                                args.use_gradle_process_resources,
                                jinja_processor)
     if data:
       project_entries.append(entry)
       srcjar_tuples.extend(
           (s, os.path.join(entry_output_dir, _SRCJARS_SUBDIR)) for s in srcjars)
       _WriteFile(os.path.join(entry_output_dir, 'build.gradle'), data)
 
   _WriteFile(os.path.join(gradle_output_dir, 'build.gradle'),
              _GenerateRootGradle(jinja_processor))
 
   _WriteFile(os.path.join(gradle_output_dir, 'settings.gradle'),
              _GenerateSettingsGradle(project_entries))
 
-  sdk_path = _RebasePath(config_json['android_sdk_root'])
+  sdk_path = _RebasePath(build_vars['android_sdk_root'])
   _WriteFile(os.path.join(gradle_output_dir, 'local.properties'),
              _GenerateLocalProperties(sdk_path))
 
   if srcjar_tuples:
     logging.warning('Building all .srcjar files...')
     targets = _RebasePath([s[0] for s in srcjar_tuples], output_dir)
     _RunNinja(output_dir, targets)
     _ExtractSrcjars(gradle_output_dir, srcjar_tuples)
   logging.warning('Project created! (%d subprojects)', len(project_entries))
   logging.warning('Generated projects work best with Android Studio 2.2')
   logging.warning('For more tips: https://chromium.googlesource.com/chromium'
                   '/src.git/+/master/docs/android_studio.md')
 
 
 if __name__ == '__main__':
   main()