Add a codereview.setting file so that `git cl upload` works.

Change-Id: Ieb43e61c14296c6caea5881a102fe4cb6d65e1df
diff --git a/codereview.settings b/codereview.settings
new file mode 100644
index 0000000..d7c8d39
--- /dev/null
+++ b/codereview.settings
@@ -0,0 +1,4 @@
+# This file is used by gcl to get repository specific information.
+GERRIT_HOST: chromium-review.googlesource.com
+GERRIT_PORT: 29418
+CODE_REVIEW_SERVER: chromium-review.googlesource.com