Adding a previews blacklist transtion entry to fieldtrial list

testing/variations/fieldtrial_testing_config.json

Index: testing/variations/fieldtrial_testing_config.json
diff --git a/testing/variations/fieldtrial_testing_config.json b/testing/variations/fieldtrial_testing_config.json
index a9141a1ea72da8fd0310b383cb19322fffa640e2..7e8fa6c1c9088b770ae7dbf8647d284973293e6b 100644
--- a/testing/variations/fieldtrial_testing_config.json
+++ b/testing/variations/fieldtrial_testing_config.json
@@ -599,6 +599,24 @@
             ]
         }
     ],
+    "DataReductionProxyPreviewsBlacklistTransition": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled"
+                },
+                {
+                    "name": "Control"

[tbansal1, 2017/06/23 17:18:02]

IIUC, there is no need to add "Control" and "Disabled" since that's just the
existing behavior.

[rkaplow, 2017/06/23 19:26:20]

also only the first one listed gets tested. So you should omit these two.

Also it looks like you're not using go/featureapi - it's recommended for all new
trials.

[RyanSturm, 2017/06/23 19:28:30]

Done. Definitely will use feature api in the future. Thanks!

+                },
+                {
+                    "name": "Disabled"
+                }
+            ]
+        }
+    ],
     "DataReductionProxyServerExperiments": [
         {
             "platforms": [