Add filetypes for .xctest and .xpc files

Those are the value used by Xcode when referencing files with
extensions xctest or xpc. Use them instead of the default value
which is likely incorrect ("text").

Bug: chromium/1071055
Change-Id: I06097444e499e1d332f08b0a1d48041c5247874c
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/8081
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
diff --git a/src/gn/xcode_object.cc b/src/gn/xcode_object.cc
index d10adf6..007ca4e 100644
--- a/src/gn/xcode_object.cc
+++ b/src/gn/xcode_object.cc
@@ -137,6 +137,8 @@
     {"xcconfig", "text.xcconfig"},
     {"xcdatamodel", "wrapper.xcdatamodel"},
     {"xcdatamodeld", "wrapper.xcdatamodeld"},
+    {"xctest", "wrapper.cfbundle"},
+    {"xpc", "wrapper.xpc-service"},
     {"xib", "file.xib"},
     {"y", "sourcecode.yacc"},
 };