Adding usage to commit message and METADATA of projects

Test: TreeHugger
Change-Id: I510495993dd31e61b6b9e6a42cc49f65ba7443ab
diff --git a/external_updater.py b/external_updater.py
index e1b19ec..e418517 100644
--- a/external_updater.py
+++ b/external_updater.py
@@ -26,7 +26,7 @@
 import json
 import os
 import sys
-import subprocess
+import textwrap
 import time
 from typing import Dict, Iterator, List, Union, Tuple, Type
 from pathlib import Path
@@ -113,8 +113,14 @@
             return
 
         rel_proj_path = fileutils.get_relative_project_path(full_path)
-        msg = 'Upgrade {} to {}\n\nTest: make\n'.format(
-            rel_proj_path, updater.latest_version)
+        msg = textwrap.dedent(f"""\
+        Upgrade {rel_proj_path} to {updater.latest_version}
+
+        This project was upgraded with external_updater.
+        Usage: tools/external_updater/updater.sh update {rel_proj_path}
+        For more info, check https://cs.android.com/android/platform/superproject/+/master:tools/external_updater/README.md
+
+        Test: TreeHugger""")
         git_utils.remove_gitmodules(full_path)
         git_utils.add_file(full_path, '*')
         git_utils.commit(full_path, msg)
diff --git a/fileutils.py b/fileutils.py
index 17202c8..861e4a6 100644
--- a/fileutils.py
+++ b/fileutils.py
@@ -85,12 +85,19 @@
         date.year = now.year
         date.month = now.month
         date.day = now.day
-    text_metadata = text_format.MessageToString(metadata)
+    usage_hint = textwrap.dedent(f"""\
+    # This project was upgraded with external_updater.
+    # Usage: tools/external_updater/updater.sh update {metadata.name}
+    # For more info, check https://cs.android.com/android/platform/superproject/+/master:tools/external_updater/README.md
+
+    """)
+    text_metadata = usage_hint + text_format.MessageToString(metadata)
     with get_metadata_path(proj_path).open('w') as metadata_file:
         if metadata.third_party.license_type == metadata_pb2.LicenseType.BY_EXCEPTION_ONLY:
            metadata_file.write(textwrap.dedent("""\
-            # *** THIS PACKAGE HAS SPECIAL LICENSING CONDITIONS.  PLEASE
-            #     CONSULT THE OWNERS AND [email protected] BEFORE
-            #     DEPENDING ON IT IN YOUR PROJECT. ***
+            # THIS PACKAGE HAS SPECIAL LICENSING CONDITIONS. PLEASE
+            # CONSULT THE OWNERS AND [email protected] BEFORE
+            # DEPENDING ON IT IN YOUR PROJECT.
+
             """))
         metadata_file.write(text_metadata)