Clean up build files

Follow up to aosp/1277469. Cleans up the build files.
Turns out the real issue was perfetto_host_executable()
obliterating the base configs when applying the forwarded ones.

Change-Id: I968d6efc134abe9c58d116ca167753fc5e7b6538

gn/standalone/proto_library.gni

diff --git a/gn/standalone/proto_library.gni b/gn/standalone/proto_library.gni
index 7ec8325..95948a3 100644
--- a/gn/standalone/proto_library.gni
+++ b/gn/standalone/proto_library.gni
@@ -186,8 +186,8 @@
       inputs = [ protoc_path ]
       deps = [ protoc_label ]
     } else {
-      inputs = [ ]
-      deps = [ ]
+      inputs = []
+      deps = []
     }
 
     # TODO(hjd): Avoid adding to deps here this.