[DevTools] Launch Background Services.

Launch the DevTools Background Services section in the application panel
with support for Background Fetch and Background Sync.

The feature flag was not deleted because it's needed for future
services.

Bug: 927726
Change-Id: Id25c52427d4e5265241db87d93fce6b3460707e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1599589
Reviewed-by: Joel Einbinder <[email protected]>
Commit-Queue: Rayan Kanso <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#658604}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 02f9355868bfe89308cb4b5ba514d3c4f739e402
diff --git a/front_end/main/Main.js b/front_end/main/Main.js
index 0e186d5..57a7bcc 100644
--- a/front_end/main/Main.js
+++ b/front_end/main/Main.js
@@ -130,7 +130,7 @@
     Runtime.experiments.register('timelineWebGL', 'Timeline: WebGL-based flamechart');
 
     Runtime.experiments.cleanUpStaleExperiments();
-    Runtime.experiments.setDefaultExperiments([]);
+    Runtime.experiments.setDefaultExperiments(['backgroundServices']);
 
     if (Host.isUnderTest() && Runtime.queryParam('test').includes('live-line-level-heap-profile.js'))
       Runtime.experiments.enableForTest('liveHeapProfile');