Reland "PM: Enable service worker relationships in graph."

This is a reland of 5fce665c

Original change's description:
> PM: Enable service worker relationships in graph.
>
> Bug: 1143281
> Change-Id: Ibc54e560a2a2a5f38c6ef48c7352c40c1b82109c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2636273
> Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
> Commit-Queue: Patrick Monette <pmonette@chromium.org>
> Reviewed-by: Patrick Monette <pmonette@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#844550}

Bug: 1143281
Change-Id: I6bfd41ce7826d14fbeb6aaabf80129d8af9816ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2642982Reviewed-by: Patrick Monette <pmonette@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845718}

components/performance_manager/features.cc

@@ -48,16 +48,7 @@ TabLoadingFrameNavigationThrottlesParams::GetParams() {
 }
 
 const base::Feature kServiceWorkerRelationshipsInGraph{
-  "ServiceWorkerRelationshipsInGraph",
-#if DCHECK_IS_ON()
-      // Enable service worker relationships by default under debug builds in
-      // order to get DCHECK failures from Alabatross.
-      // TODO(https://crbug.com/1143281): Revert once there's sufficient data.
-      base::FEATURE_ENABLED_BY_DEFAULT
-#else
-      base::FEATURE_DISABLED_BY_DEFAULT
-#endif
-};
+    "ServiceWorkerRelationshipsInGraph", base::FEATURE_ENABLED_BY_DEFAULT};
 
 }  // namespace features
 }  // namespace performance_manager