Create proper wrapper scripts to decouple from swarm_client.

scripts/master/factory/swarm_commands.py

Index: scripts/master/factory/swarm_commands.py
diff --git a/scripts/master/factory/swarm_commands.py b/scripts/master/factory/swarm_commands.py
index 89166e8f71c2283bc68c02c731a4e4dff5749515..355b8afbfefd580af25fbfaa6bee13b32b40e675 100644
--- a/scripts/master/factory/swarm_commands.py
+++ b/scripts/master/factory/swarm_commands.py
@@ -89,6 +89,23 @@ class SwarmShellForTriggeringTests(shell.ShellCommand):
     swarm_tests_hash_mapping = commands.GetProp(self, 'swarm_hashes', {})
 
     command = self.command[:]
+
+    # Determine the priority. (Lower the more important) There's 3 levels:
+    # - Continuous Integration: 10
+    # - CQ Try Jobs:            50
+    # - Try Jobs:               90
+    # Default priority is      100
+    # So determine the priority.
+    priority = 10
+    requester = commands.GetProp(self, 'requester', None)
+    if requester == 'commit-bot@chromium.org':
+      # A CQ job.
+      priority = 50
+    elif requester or commands.GetProp(self, 'testfilter', None):
+      # A try job.
+      priority = 90
+    command.extend(('--priority', str(priority)))

[Isaac (away), 2013/08/14 20:23:18]

Is there a way to move this logic to a slaves script?  It looks OK but we might
want to tweak it without needed a ts restart.

I'm going to pull in robbie to get a second opinion.

+
     for swarm_test in self.tests:
       if swarm_tests_hash_mapping.get(swarm_test.test_name):
         command.extend(