blink_rename_merge_helper: Implement run.py loader stub

tools/blink_rename_merge_helper/README.md

Index: tools/blink_rename_merge_helper/README.md
diff --git a/tools/blink_rename_merge_helper/README.md b/tools/blink_rename_merge_helper/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..d9bc67e593196fd4fe4e9a9f16be6001a4389be4
--- /dev/null
+++ b/tools/blink_rename_merge_helper/README.md
@@ -0,0 +1,14 @@
+Tool to help manage merge conflicts from the Blink rename. The tool is committed
+into the Chromium repository. However, with the exception of the `run.py` loader
+stub, everything else is fetched from the chromium-blink-rename Google Storage
+bucket at runtime.
+
+COMPONENTS is a list of component names and hashes; the tool always fetches the
+latest COMPONENTS manifest from Google Storage. The checked-in copy exists as a
+reference, so that changes can be reviewed and tracked. In addition, if the
+component name is of the form `name-platform`, `name` is used as the actual
+component name, while `platform` is passed to `download_from_google_storage.py`
+as the platform argument. This is used to version per-platform binaries.
+
+Use `upload_to_google_storage.py -b chromium-blink-rename -a pylib` to upload
+new versions of the pylib.