Ship navigator.scheduling.isInputPending()

Intent to ship approved here:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/8Vt2atMrNNs

Bug: 910421
Change-Id: Ie399046d6a0116d76e86b0daa2bddce306f1c24a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2443493Reviewed-by: Philip Rogers <pdr@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Andrew Comminos <acomminos@fb.com>
Auto-Submit: Andrew Comminos <acomminos@fb.com>
Cr-Commit-Position: refs/heads/master@{#812973}

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -762,7 +762,7 @@
     {
       name: "ExperimentalIsInputPending",
       origin_trial_feature_name: "ExperimentalIsInputPending",
-      status: "experimental"
+      status: "stable"
     },
     // Enables a DOM-exposed interface to profile client JS.
     // https://github.com/WICG/js-self-profiling

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -4615,6 +4615,7 @@ interface Navigator
     getter presentation
     getter product
     getter productSub
+    getter scheduling
     getter serviceWorker
     getter storage
     getter usb
@@ -6891,6 +6892,10 @@ interface SVGViewElement : SVGElement
     getter zoomAndPan
     method constructor
     setter zoomAndPan
+interface Scheduling
+    attribute @@toStringTag
+    method constructor
+    method isInputPending
 interface Screen
     attribute @@toStringTag
     getter availHeight