Reland of Make generate_gradle.py work with preview SDKs.

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 glob
@@ skipping 74 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 _ReadPropertiesFile(path):
+  with open(path) as f:
+    return dict(l.rstrip().split('=', 1) for l in f if '=' in l)
 
 
 def _RunNinja(output_dir, args):
   cmd = ['ninja', '-C', output_dir, '-j1000']
   cmd.extend(args)
   logging.info('Running: %r', cmd)
   subprocess.check_call(cmd)
 
 
 def _QueryForAllGnTargets(output_dir):
@@ skipping 399 matching lines @@
     else:
       target_type = 'java_binary'
       variables['main_class'] = gradle['main_class']
   else:
     return None
 
   variables['target_name'] = os.path.splitext(deps_info['name'])[0]
   variables['template_type'] = target_type
   variables['use_gradle_process_resources'] = (
       generator.use_gradle_process_resources)
-  variables['build_tools_version'] = (
-      build_vars['android_sdk_build_tools_version'])
-  variables['compile_sdk_version'] = build_vars['android_sdk_version']
+  source_properties = _ReadPropertiesFile(
+      _RebasePath(os.path.join(build_vars['android_sdk_build_tools'],
+                               'source.properties')))
+  variables['build_tools_version'] = source_properties['Pkg.Revision']
+  variables['compile_sdk_version'] = (
+      'android-%s' % build_vars['android_sdk_version'])
   variables['main'] = generator.Generate(entry)
   bootclasspath = gradle.get('bootclasspath')
   if bootclasspath:
     # Must use absolute path here.
     variables['bootclasspath'] = _RebasePath(bootclasspath)
   if entry.android_test_entry:
     variables['android_test'] = generator.Generate(
         entry.android_test_entry)
     for key, value in variables['android_test'].iteritems():
       if isinstance(value, list):
@@ skipping 123 matching lines @@
   run_tests_helper.SetLogLevel(args.verbose_count)
 
   # TODO(wnwen): Fix packaging so that gradle resources work in this case.
   if args.use_gradle_process_resources:
     assert args.split_projects, (
         'Gradle resources does not yet work without --split-projects.')
 
   _gradle_output_dir = os.path.abspath(
       args.project_dir.replace('$CHROMIUM_OUTPUT_DIR', output_dir))
   jinja_processor = jinja_template.JinjaProcessor(_FILE_DIR)
-  build_vars = _ReadBuildVars(output_dir)
+  build_vars = _ReadPropertiesFile(os.path.join(output_dir, 'build_vars.txt'))
   generator = _ProjectContextGenerator(_gradle_output_dir, build_vars,
       args.use_gradle_process_resources, jinja_processor, args.split_projects)
   logging.warning('Creating project at: %s', generator.project_dir)
 
   if args.all:
     # Run GN gen if necessary (faster than running "gn gen" in the no-op case).
     _RunNinja(constants.GetOutDirectory(), ['build.ninja'])
     # Query ninja for all __build_config targets.
     targets = _QueryForAllGnTargets(output_dir)
   else:
@@ skipping 60 matching lines @@
     _ExtractZips(generator.project_dir, zip_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()