Enable InspectDownloadedRarFiles for testing on bots

CL to enable on Dev and Canary: http://cl/200424143

Bug: 750327
Change-Id: Ica7ac69480d5739d4cc35d692b911c51f6547b15
Reviewed-on: https://chromium-review.googlesource.com/1104949Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568494}

testing/variations/fieldtrial_testing_config.json

@@ -1879,6 +1879,24 @@
             ]
         }
     ],
+    "InspectDownloadedRarFiles": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "win"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "InspectDownloadedRarFiles"
+                    ]
+                }
+            ]
+        }
+    ],
     "InstanceID": [
         {
             "platforms": [