rebaseline-cl: trigger all try jobs in one invocation of git cl try.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py b/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py
index 03267c4e376e540782b4d1f51e53c097fa9884ac..5157098706bc81e1772549eb0df47dc824ba6787 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py
@@ -132,14 +132,11 @@ class RebaselineCL(AbstractParallelRebaselineCommand):
 
         if builders_without_builds:
             _log.info('Triggering try jobs for:')
+            command = ['try']
             for builder in sorted(builders_without_builds):
                 _log.info('  %s', builder)
-            # If the builders may be under different masters, then they cannot
-            # all be started in one invocation of git cl try without providing
-            # master names. Doing separate invocations is slower, but always works
-            # even when there are builders under different master names.
-            for builder in sorted(builders_without_builds):
-                self.git_cl().run(['try', '-b', builder])
+                command.extend(['-b', builder])
+            self.git_cl().run(command)
 
         return bool(builders_with_pending_builds or builders_without_builds)