[Cronet] add base proguard flags

components/cronet/tools/generate_proguard_file.py

Index: components/cronet/tools/generate_proguard_file.py
diff --git a/components/cronet/tools/generate_proguard_file.py b/components/cronet/tools/generate_proguard_file.py
new file mode 100755
index 0000000000000000000000000000000000000000..6d7e530a0178a688d85c1f61a4ad71c66e7a52b0
--- /dev/null
+++ b/components/cronet/tools/generate_proguard_file.py
@@ -0,0 +1,33 @@
+#!/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.
+
+import optparse
+import sys
+
+# Combines files in |input_files| as one proguard file and write that to
+# |output_file|
+def GenerateProguardFile(output_file, input_files):
+  try:
+    with open(output_file, "wb") as target:
+      for input_file in input_files:
+        f = open(input_file, "rb")
+        for line in f:
+          target.write(line)
+  except IOError:
+    raise Exception("Proguard file generation failed")
+
+
+def main():
+  parser = optparse.OptionParser()
+  parser.add_option('--output-file',
+          help='Output file for the generated proguard file')
+
+  options, input_files = parser.parse_args()
+  GenerateProguardFile(options.output_file, input_files)
+
+
+if __name__ == '__main__':
+  sys.exit(main())