Add a new chromium.mojo master

masters/master.chromium.mojo/master_source_cfg.py

Index: masters/master.chromium.mojo/master_source_cfg.py
diff --git a/scripts/tools/buildbot_tool_templates/master_source_cfg.py b/masters/master.chromium.mojo/master_source_cfg.py
similarity index 61%
copy from scripts/tools/buildbot_tool_templates/master_source_cfg.py
copy to masters/master.chromium.mojo/master_source_cfg.py
index 324e2294caad03df6968b67a23d1842444ac74b5..75fc66c553d44506154aec0f915ef7ac6465c07f 100644
--- a/scripts/tools/buildbot_tool_templates/master_source_cfg.py
+++ b/masters/master.chromium.mojo/master_source_cfg.py
@@ -2,13 +2,17 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# This file is used by scripts/tools/buildbot-tool to generate master configs.
+# This file was generated from
+# scripts/tools/buildbot_tool_templates/master_source_cfg.py
+# by scripts/tools/buildbot-tool.
+# DO NOT EDIT BY HAND!
+
 
 from master import gitiles_poller
 
 
 def Update(config, active_master, c):
   master_poller = gitiles_poller.GitilesPoller(
-      '%(git_repo_url)s')
+      'https://chromium.googlesource.com/src/src.git')
 
   c['change_source'].append(master_poller)