conv_linker_config proto supports multiple input json files

conv_linker_config proto -s input1.json:input2.json generates a merged
proto output file.

Bug: 264330513
Test: conv_linker_config proto -s input1.json:input2.json
Change-Id: I4806fc606d115c42a1c745fba67960ce6db8c8d7

scripts/conv_linker_config.py

@@ -27,13 +27,15 @@ from google.protobuf.text_format import MessageToString
 
 
 def Proto(args):
+    pb = linker_config_pb2.LinkerConfig()
+    for input in args.source.split(':'):
         json_content = ''
-    with open(args.source) as f:
+        with open(input) as f:
             for line in f:
                 if not line.lstrip().startswith('//'):
                     json_content += line
         obj = json.loads(json_content, object_pairs_hook=collections.OrderedDict)
-    pb = ParseDict(obj, linker_config_pb2.LinkerConfig())
+        ParseDict(obj, pb)
     with open(args.output, 'wb') as f:
         f.write(pb.SerializeToString())
 
@@ -104,7 +106,7 @@ def GetArgParser():
         '--source',
         required=True,
         type=str,
-        help='Source linker configuration file in JSON.')
+        help='Colon-separated list of linker configuration files in JSON.')
     parser_proto.add_argument(
         '-o',
         '--output',