Remove UpdateHoverPostLayout runtime enable flag.

This feature has shipped for a number of releases. Remove the dynamic
setting of the feature.

BUG=488886

Change-Id: I76d1935cb5ff7e529a7943c994632cde41568f90
Reviewed-on: https://chromium-review.googlesource.com/1037929
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Mustaq Ahmed <mustaq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555199}

third_party/blink/renderer/core/frame/local_frame_view.cc

@@ -2613,19 +2613,10 @@ void LocalFrameView::PerformPostLayoutTasks() {
   DCHECK(frame_->GetDocument());
 
   FontFaceSetDocument::DidLayout(*frame_->GetDocument());
-  // Cursor update scheduling is done by the local root, which is the main frame
-  // if there are no RemoteFrame ancestors in the frame tree. Use of
-  // localFrameRoot() is discouraged but will change when cursor update
-  // scheduling is moved from EventHandler to PageEventHandler.
-
   // Fire a fake a mouse move event to update hover state and mouse cursor, and
   // send the right mouse out/over events.
-  if (RuntimeEnabledFeatures::UpdateHoverPostLayoutEnabled()) {
-    frame_->GetEventHandler().DispatchFakeMouseMoveEventSoon(
-        MouseEventManager::FakeMouseMoveReason::kPerFrame);
-  } else {
-    GetFrame().LocalFrameRoot().GetEventHandler().ScheduleCursorUpdate();
-  }
+  frame_->GetEventHandler().DispatchFakeMouseMoveEventSoon(
+      MouseEventManager::FakeMouseMoveReason::kPerFrame);
 
   UpdateGeometriesIfNeeded();
 

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1251,10 +1251,6 @@
       name: "UnifiedTouchAdjustment",
       status: "experimental",
     },
-    {
-      name: "UpdateHoverPostLayout",
-      status: "stable",
-    },
     {
       name: "UserActivationV2",
     },