Support for |change| argument to |GetPreferredTrySlaves()|, try 2.

Needed to make it so changes containing only *.mm are only sent to Mac trybots by default.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/8059009

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@102930 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/gcl.py b/gcl.py
index 32286b2..72a83fd 100755
--- a/gcl.py
+++ b/gcl.py
@@ -961,11 +961,21 @@
     if change_info.patchset:
       trychange_args.extend(["--patchset", str(change_info.patchset)])
     file_list = change_info.GetFileNames()
+    change = presubmit_support.SvnChange(change_info.name,
+                                         change_info.description,
+                                         change_info.GetLocalRoot(),
+                                         change_info.GetFiles(),
+                                         change_info.issue,
+                                         change_info.patchset,
+                                         None)
   else:
     file_list = []
+    change = None
+
   trychange_args.extend(args)
   return trychange.TryChange(
       trychange_args,
+      change=change,
       file_list=file_list,
       swallow_exception=swallow_exception,
       prog='gcl try',