Put the path to protobuf in front.

chrome/browser/resources/safe_browsing/gen_file_type_proto.py

Index: chrome/browser/resources/safe_browsing/gen_file_type_proto.py
diff --git a/chrome/browser/resources/safe_browsing/gen_file_type_proto.py b/chrome/browser/resources/safe_browsing/gen_file_type_proto.py
index 6700142c0c7b5371fbc9fc7d015187c417b7207e..3c4b5081053de011cba2a28d4998ee0e6418a98b 100755
--- a/chrome/browser/resources/safe_browsing/gen_file_type_proto.py
+++ b/chrome/browser/resources/safe_browsing/gen_file_type_proto.py
@@ -12,10 +12,11 @@ import sys
 
 
 def ConvertProto(opts):
-
   # Find the proto code
   for path in opts.path:
-    sys.path.append(path)
+    # Put the path to our proto libraries in front, so that we don't use system
+    # protobuf.
+    sys.path.insert(1, path)
 
   import download_file_types_pb2 as config_pb2
   import google.protobuf.text_format as text_format