DevTools: [CSS] remove CSS Regions experiment from DevTools.

Source/devtools/front_end/Settings.js

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 261 matching lines @@
 WebInspector.ExperimentsSettings = function()
 {
     this._setting = WebInspector.settings.createSetting("experiments", {});
     this._experiments = [];
     this._enabledForTest = {};
 
     // Add currently running experiments here.
     this.asyncStackTraces = this._createExperiment("asyncStackTraces", "Enable support for async stack traces");
     this.fileSystemInspection = this._createExperiment("fileSystemInspection", "FileSystem inspection");
     this.canvasInspection = this._createExperiment("canvasInspection ", "Canvas inspection");
-    this.cssRegions = this._createExperiment("cssRegions", "CSS Regions Support");
     this.frameworksDebuggingSupport = this._createExperiment("frameworksDebuggingSupport", "Enable frameworks debugging support");
     this.layersPanel = this._createExperiment("layersPanel", "Show Layers panel");
     this.stepIntoSelection = this._createExperiment("stepIntoSelection", "Show step-in candidates while debugging.");
     this.doNotOpenDrawerOnEsc = this._createExperiment("doNotOpenDrawerWithEsc", "Do not open drawer on Esc");
     this.showEditorInDrawer = this._createExperiment("showEditorInDrawer", "Show editor in drawer");
     this.gpuTimeline = this._createExperiment("gpuTimeline", "Show GPU data on timeline");
     this.applyCustomStylesheet = this._createExperiment("applyCustomStylesheet", "Allow custom UI themes");
     this.workersInMainWindow = this._createExperiment("workersInMainWindow", "Show workers in main window");
     this.dockToLeft = this._createExperiment("dockToLeft", "Enable dock to left mode");
     this.allocationProfiler = this._createExperiment("allocationProfiler", "Enable JavaScript heap allocation profiler");
@@ skipping 197 matching lines @@
     {
         // If there are too many breakpoints in a storage, it is likely due to a recent bug that caused
         // periodical breakpoints duplication leading to inspector slowness.
         if (breakpointsSetting.get().length > maxBreakpointsCount)
             breakpointsSetting.set([]);
     }
 }
 
 WebInspector.settings = new WebInspector.Settings();
 WebInspector.experimentsSettings = new WebInspector.ExperimentsSettings();