Convert most Chromium presubmit files to use new multiple-tryserver-compatible protocol

chrome/common/net/PRESUBMIT.py

Index: chrome/common/net/PRESUBMIT.py
diff --git a/chrome/common/net/PRESUBMIT.py b/chrome/common/net/PRESUBMIT.py
index 01292eff5d73eeb9f7f04c037cc3ee6889632822..a904e7bf70ea03dbf60a2dd41985e0bcb6b8817f 100644
--- a/chrome/common/net/PRESUBMIT.py
+++ b/chrome/common/net/PRESUBMIT.py
@@ -8,9 +8,11 @@ See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details on the presubmit API built into gcl.
 """
 
-def GetPreferredTrySlaves():
-  return [
-    'linux_rel:sync_integration_tests',
-    'mac_rel:sync_integration_tests',
-    'win_rel:sync_integration_tests',
-  ]
+def GetPreferredTryMasters(project, change):
+  return {
+    'tryserver.chromium': {
+      'linux_rel': set(['sync_integration_tests']),
+      'mac_rel': set(['sync_integration_tests']),
+      'win_rel': set(['sync_integration_tests']),
+    }
+  }