Pass implementation object to supplemental classes by reference

Source/core/dom/WheelController.cpp

 /*
  * Copyright (C) 2013 Google, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 
 #include "core/dom/Document.h"
 #include "core/events/ThreadLocalEventNames.h"
 #include "core/events/WheelEvent.h"
 #include "core/frame/Frame.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 
 namespace WebCore {
 
-WheelController::WheelController(Document* document)
-    : DOMWindowLifecycleObserver(document->domWindow())
+WheelController::WheelController(Document& document)
+    : DOMWindowLifecycleObserver(document.domWindow())
     , m_wheelEventHandlerCount(0)
 {
 }
 
 WheelController::~WheelController()
 {
 }
 
 const char* WheelController::supplementName()
 {
     return "WheelController";
 }
 
-WheelController* WheelController::from(Document* document)
+WheelController* WheelController::from(Document& document)
 {
     WheelController* controller = static_cast<WheelController*>(DocumentSupplement::from(document, supplementName()));
     if (!controller) {
         controller = new WheelController(document);
         DocumentSupplement::provideTo(document, supplementName(), adoptPtr(controller));
     }
     return controller;
 }
 
-static void wheelEventHandlerCountChanged(Document* document)
+static void wheelEventHandlerCountChanged(Document& document)
 {
-    Page* page = document->page();
+    Page* page = document.page();
     if (!page)
         return;
 
     ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator();
     if (!scrollingCoordinator)
         return;
 
-    FrameView* frameView = document->view();
+    FrameView* frameView = document.view();
     if (!frameView)
         return;
 
     scrollingCoordinator->frameViewWheelEventHandlerCountChanged(frameView);
 }
 
-void WheelController::didAddWheelEventHandler(Document* document)
+void WheelController::didAddWheelEventHandler(Document& document)
 {
     ++m_wheelEventHandlerCount;
-    Page* page = document->page();
+    Page* page = document.page();
     Frame* mainFrame = page ? page->mainFrame() : 0;
     if (mainFrame)
         mainFrame->notifyChromeClientWheelEventHandlerCountChanged();
 
     wheelEventHandlerCountChanged(document);
 }
 
-void WheelController::didRemoveWheelEventHandler(Document* document)
+void WheelController::didRemoveWheelEventHandler(Document& document)
 {
     ASSERT(m_wheelEventHandlerCount > 0);
     --m_wheelEventHandlerCount;
-    Page* page = document->page();
+    Page* page = document.page();
     Frame* mainFrame = page ? page->mainFrame() : 0;
     if (mainFrame)
         mainFrame->notifyChromeClientWheelEventHandlerCountChanged();
 
     wheelEventHandlerCountChanged(document);
 }
 
 void WheelController::didAddEventListener(DOMWindow* window, const AtomicString& eventType)
 {
     if (eventType != EventTypeNames::wheel && eventType != EventTypeNames::mousewheel)
         return;
 
     Document* document = window->document();
-    didAddWheelEventHandler(document);
+    ASSERT(document);
+    didAddWheelEventHandler(*document);
 }
 
 void WheelController::didRemoveEventListener(DOMWindow* window, const AtomicString& eventType)
 {
     if (eventType != EventTypeNames::wheel && eventType != EventTypeNames::mousewheel)
         return;
 
     Document* document = window->document();
-    didRemoveWheelEventHandler(document);
+    ASSERT(document);
+    didRemoveWheelEventHandler(*document);
 }
 
 } // namespace WebCore