[Devtools] Un-experiment color contrast line

Bug: 514674
Change-Id: I60aa5d38cb31b52f74a053f2dd35a5db675a2fea
Reviewed-on: https://chromium-review.googlesource.com/627346
Commit-Queue: Pavel Feldman <pfeldman@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522125}

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

@@ -163,7 +163,7 @@ Main.Main = class {
     Runtime.experiments.setDefaultExperiments([
       'continueToLocationMarkers', 'autoAttachToCrossProcessSubframes', 'objectPreviews', 'persistence2',
       'networkGroupingRequests', 'timelineColorByProduct', 'accessibilityInspection', 'logManagement',
-      'performanceMonitor', 'stepIntoAsync'
+      'performanceMonitor', 'stepIntoAsync', 'colorContrastRatio'
     ]);
   }