Add PassiveDocumentWheelEventListeners to fieldtrial_testing_config

Please find the intent ot implement here:
https://groups.google.com/a/chromium.org/forum/?hl=en#!topic/blink-dev/53q-wRk5QkA

Bug: 626196
Change-Id: Id77ceb7352629a6a9417617602d330919904ed44
Reviewed-on: https://chromium-review.googlesource.com/1183538Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Sahel Sharify <sahel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585020}

testing/variations/fieldtrial_testing_config.json

@@ -3083,6 +3083,25 @@
             ]
         }
     ],
+    "PassiveDocumentWheelEventListeners": [
+        {
+            "platforms": [
+                "android",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "PassiveDocumentWheelEventListeners"
+                    ]
+                }
+            ]
+        }
+    ],
     "PassiveEventListenersDueToFling": [
         {
             "platforms": [