constants: convert CHROMITE_DIR to a Path object

BUG=None
TEST=CQ passes

Change-Id: I826e6fcddcd205435c65df69b030caf43ea3ab29
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4358397
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Ram Chandrasekar <rchandrasekar@google.com>
diff --git a/api/compile_build_api_proto.py b/api/compile_build_api_proto.py
index 317a3ec..485ded9 100644
--- a/api/compile_build_api_proto.py
+++ b/api/compile_build_api_proto.py
@@ -52,13 +52,13 @@
     def get_gen_dir(self) -> Path:
         """Get the chromite/api directory path."""
         if self is ProtocVersion.SDK:
-            return Path(constants.CHROMITE_DIR) / "api" / "gen_sdk"
+            return constants.CHROMITE_DIR / "api" / "gen_sdk"
         else:
-            return Path(constants.CHROMITE_DIR) / "api" / "gen"
+            return constants.CHROMITE_DIR / "api" / "gen"
 
     def get_proto_dir(self) -> Path:
         """Get the proto directory for the target protoc."""
-        return Path(constants.CHROMITE_DIR) / "infra" / "proto"
+        return constants.CHROMITE_DIR / "infra" / "proto"
 
     def get_protoc_command(self, cipd_root: Optional[Path] = None) -> Path:
         """Get protoc command path."""