gn2bp: properly add proto_deps

Test: //components/cronet/android:cronet
Change-Id: I1583db83d3cd51d734c9d7252f0c5ff6194f9131
diff --git a/tools/gn2bp/gn_utils.py b/tools/gn2bp/gn_utils.py
index 31cc2e1..6f3c787 100644
--- a/tools/gn2bp/gn_utils.py
+++ b/tools/gn2bp/gn_utils.py
@@ -280,7 +280,9 @@
       target.proto_paths.update(self.get_proto_paths(proto_desc))
       target.proto_exports.update(self.get_proto_exports(proto_desc))
       target.proto_in_dir = self.get_proto_in_dir(proto_desc)
-      target.deps.update(proto_desc.get('deps', []))
+      for gn_proto_deps_name in proto_desc.get('deps', []):
+        dep = self.parse_gn_desc(gn_desc, gn_proto_deps_name)
+        target.deps.add(dep.name)
       target.arch[arch].sources.update(proto_desc.get('sources', []))
       assert (all(x.endswith('.proto') for x in target.arch[arch].sources))
     elif target.type == 'source_set':