Added fieldtrial_testing_config entry for Client-side LoFi.

Bug: 
Change-Id: I9f792d5b74dd28ee9442725a182a69de62c4f66e
Reviewed-on: https://chromium-review.googlesource.com/700794Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Scott Little <sclittle@chromium.org>
Commit-Queue: Scott Little <sclittle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506482}

testing/variations/fieldtrial_testing_config.json

@@ -2469,6 +2469,25 @@
             ]
         }
     ],
+    "PreviewsClientLoFi": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled_2G_Replace_Server_Placeholders",
+                    "params": {
+                        "max_allowed_effective_connection_type": "2G",
+                        "replace_server_placeholders": "true"
+                    },
+                    "enable_features": [
+                        "ClientLoFi"
+                    ]
+                }
+            ]
+        }
+    ],
     "PrintPdfAsImage": [
         {
             "platforms": [