Include flag_check hook for "packages/SystemUI"

Parse arguments in flag_check.py.

- msg = commit message
- files = modified files paths
- project = repo_path

Using project we can filter further for "frameworks/base" and see if
files starts with "packages/SystemUI" and then apply Flags check.

Bug: 306262821
Test: Manual
Flag: NA
Change-Id: I9b678344512527ec8b79aa458dae9f54fb4c61ba
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
index 015487d..b42f7bc 100644
--- a/PREUPLOAD.cfg
+++ b/PREUPLOAD.cfg
@@ -28,3 +28,6 @@
 ktfmt_hook = ${REPO_ROOT}/external/ktfmt/ktfmt.py --check -i ${REPO_ROOT}/frameworks/base/ktfmt_includes.txt ${PREUPLOAD_FILES}
 
 ktlint_hook = ${REPO_ROOT}/prebuilts/ktlint/ktlint.py --no-verify-format -f ${PREUPLOAD_FILES}
+
+# This flag check hook runs only for "packages/SystemUI" subdirectory. If you want to include this check for other subdirectories, please modify flag_check.py.
+flag_hook = ${REPO_ROOT}/frameworks/base/packages/SystemUI/flag_check.py --msg=${PREUPLOAD_COMMIT_MESSAGE} --files=${PREUPLOAD_FILES} --project=${REPO_PATH}