Add --build_dir arg to build_aar.py

tools_webrtc/android/build_aar.py

Index: tools_webrtc/android/build_aar.py
diff --git a/tools_webrtc/android/build_aar.py b/tools_webrtc/android/build_aar.py
index 54272e979e446c25de831aa36f24624ed335976f..ff62049a903b23e62504805f651ae88ea651db04 100755
--- a/tools_webrtc/android/build_aar.py
+++ b/tools_webrtc/android/build_aar.py
@@ -46,6 +46,8 @@ TARGETS = [
 
 def _ParseArgs():
   parser = argparse.ArgumentParser(description='libwebrtc.aar generator.')
+  parser.add_argument('--build-dir',
+      help='Build dir. By default will create and use temporary dir.')
   parser.add_argument('--output', default='libwebrtc.aar',
       help='Output file of the script.')
   parser.add_argument('--arch', default=DEFAULT_ARCHS, nargs='*',
@@ -162,18 +164,19 @@ def main():
   args = _ParseArgs()
   logging.basicConfig(level=logging.DEBUG if args.verbose else logging.INFO)
 
-  tmp_dir = tempfile.mkdtemp()
+  build_dir = args.build_dir if args.build_dir else tempfile.mkdtemp()
 
   for arch in args.arch:
-    Build(tmp_dir, arch, args.use_goma, args.extra_gn_args)
+    Build(build_dir, arch, args.use_goma, args.extra_gn_args)
 
   with zipfile.ZipFile(args.output, 'w') as aar_file:
     # Architecture doesn't matter here, arbitrarily using the first one.
-    CollectCommon(aar_file, tmp_dir, args.arch[0])
+    CollectCommon(aar_file, build_dir, args.arch[0])
     for arch in args.arch:
-      Collect(aar_file, tmp_dir, arch)
+      Collect(aar_file, build_dir, arch)
 
-  shutil.rmtree(tmp_dir, True)
+  if not args.build_dir:
+    shutil.rmtree(build_dir, True)
 
 
 if __name__ == '__main__':