Remove visibilityChangeOnUnload runtime flag (as it's shipped)

third_party/WebKit/Source/core/dom/Document.cpp

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index ecf025f9b8bbdf102ff34cfc044e347942b63755..f83857eab977008fb5d1f8714aafceadbf8a7dcf 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -3244,8 +3244,7 @@ void Document::DispatchUnloadEvents() {
 
       PageVisibilityState visibility_state = GetPageVisibilityState();
       load_event_progress_ = kUnloadVisibilityChangeInProgress;
-      if (visibility_state != kPageVisibilityStateHidden &&
-          RuntimeEnabledFeatures::visibilityChangeOnUnloadEnabled()) {
+      if (visibility_state != kPageVisibilityStateHidden) {
         // Dispatch visibilitychange event, but don't bother doing
         // other notifications as we're about to be unloaded.
         DispatchEvent(Event::CreateBubble(EventTypeNames::visibilitychange));