Add isolate.clean_isolated_files and use in all related recipes.

scripts/slave/recipe_modules/isolate/resources/find_isolated_tests.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Scans build output directory for .isolated files, calculates their SHA1
 hashes and stores final list in JSON document.
 
 Used to figure out what tests were build in isolated mode to trigger these
 tests to run on swarming.
@@ skipping 18 matching lines @@
     while True:
       chunk = f.read(1024*1024)
       if not chunk:
         break
       digest.update(chunk)
   return digest.hexdigest()
 
 
 def main():
   parser = optparse.OptionParser(
-      usage='%prog --build-dir <path> --output-json <path>',
+      usage='%prog --build-dir <path> '
+          '[--output-json <path> | --clean-isolated-files]',
       description=sys.modules[__name__].__doc__)
   parser.add_option(
       '--build-dir',
       help='Path to a directory to search for *.isolated files.')
   parser.add_option(
       '--output-json',
-      help='File to dump JSON results into.')
+      help='File to dump JSON results into. '
+          'Mutually exclusive with --clean-isolated-files.')
+  parser.add_option(
+      '--clean-isolated-files',
+      action='store_true',
+      help='Whether to clean out all .isolated files. '
+          'Mutually exclusive with --output-json.')
 
   options, _ = parser.parse_args()
   if not options.build_dir:
     parser.error('--build-dir option is required')
-  if not options.output_json:
-    parser.error('--output-json option is required')
+  if not (options.output_json or options.clean_isolated_files):
+    parser.error('either --output-json or --clean-isolated-files is required')
+  if options.output_json and options.clean_isolated_files:
+    parser.error('only one of --output-json and '
+                 '--clean-isolated-files is allowed')
 
   result = {}
 
   # Get the file hash values and output the pair.
   pattern = os.path.join(options.build_dir, '*.isolated')
   for filepath in sorted(glob.glob(pattern)):
     test_name = os.path.splitext(os.path.basename(filepath))[0]
     if re.match(r'^.+?\.\d$', test_name):
       # It's a split .isolated file, e.g. foo.0.isolated. Ignore these.
       continue
 
-    sha1_hash = hash_file(filepath)
-    result[test_name] = sha1_hash
+    if options.clean_isolated_files:
+      # TODO(csharp): Remove deletion entirely once the isolate
+      # tracked dependencies are inputs for the isolated files.
+      # http://crbug.com/419031
+      os.remove(filepath)
+    else:
+      sha1_hash = hash_file(filepath)
+      result[test_name] = sha1_hash
 
-  with open(options.output_json, 'wb') as f:
-    json.dump(result, f)
+  if options.output_json:
+    with open(options.output_json, 'wb') as f:
+      json.dump(result, f)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())