[Devtools] Remove overrides from enabled by default for beta

Disbles overrides by default.

TBR=pfeldman
BUG=754371

Change-Id: Icd88688a94842bd6ff96566d41e07f6615caae32
Reviewed-on: https://chromium-review.googlesource.com/801574
Commit-Queue: Blaise Bruer <allada@chromium.org>
Reviewed-by: Blaise Bruer <allada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520700}

third_party/WebKit/Source/devtools/front_end/main/Main.js

@@ -150,12 +150,14 @@ Main.Main = class {
         Runtime.experiments.enableForTest('accessibilityInspection');
       if (testPath.indexOf('console-sidebar/') !== -1)
         Runtime.experiments.enableForTest('logManagement');
+      if (testPath.indexOf('overrides/') !== -1)
+        Runtime.experiments.enableForTest('networkPersistence');
     }
 
     Runtime.experiments.setDefaultExperiments([
       'continueToLocationMarkers', 'autoAttachToCrossProcessSubframes', 'objectPreviews', 'persistence2',
-      'networkGroupingRequests', 'timelineColorByProduct', 'accessibilityInspection', 'networkPersistence',
-      'logManagement', 'performanceMonitor'
+      'networkGroupingRequests', 'timelineColorByProduct', 'accessibilityInspection', 'logManagement',
+      'performanceMonitor'
     ]);
   }