[scheduler] Removing an unnecessary ThreadUtils call.

This function is already guaranteed to run on the UI thread (2 function
calls above there's an assertOnUiThread).

Bug: 863341
Change-Id: Ibe4a63ddaa324b8f9c64b2a7f8fd708cbba5b010
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1590097Reviewed-by: Karolina Soltys <ksolt@chromium.org>
Reviewed-by: Matt Reynolds <mattreynolds@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Auto-Submit: Karolina Soltys <ksolt@chromium.org>
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656346}

services/device/geolocation/android/java/src/org/chromium/device/geolocation/LocationProviderAndroid.java

@@ -139,13 +139,9 @@ public class LocationProviderAndroid implements LocationListener, LocationProvid
         final Location location =
                 mLocationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
         if (location != null) {
-            ThreadUtils.runOnUiThread(new Runnable() {
-                @Override
-                public void run() {
+            ThreadUtils.assertOnUiThread();
             LocationProviderAdapter.onNewLocationAvailable(location);
         }
-            });
-        }
         return true;
     }