Add SimplifyHttpsIndicator testing config

This adds a field trial testing config for the SimplifyHttpsIndicator
experiment (https://crbug.com/803138), using a default of the
EV-to-Secure variation.

Bug: 803501
Change-Id: I7bc008d9c9a447d69ce9038f4ef06872407cff43
Reviewed-on: https://chromium-review.googlesource.com/956354
Commit-Queue: Christopher Thompson <cthomp@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542016}

testing/variations/fieldtrial_testing_config.json

@@ -3535,6 +3535,27 @@
             ]
         }
     ],
+    "SimplifyHttpsIndicator": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "win",
+                "mac"
+            ],
+            "experiments": [
+                {
+                    "name": "EvToSecure",
+                    "params": {
+                        "treatment": "ev-to-secure"
+                    },
+                    "enable_features": [
+                        "SimplifyHttpsIndicator"
+                    ]
+                }
+            ]
+        }
+    ],
     "SocketReadIfReady": [
         {
             "platforms": [