Use refs for non-null GraphicsContext, Scrollbar, etc. in scrollbar related code

third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp

 /*
  * Copyright (C) 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 258 matching lines @@
     removeWebScrollbarLayer(scrollableArea, VerticalScrollbar);
 }
 
 void ScrollingCoordinator::removeWebScrollbarLayer(ScrollableArea* scrollableArea, ScrollbarOrientation orientation)
 {
     ScrollbarMap& scrollbars = orientation == HorizontalScrollbar ? m_horizontalScrollbars : m_verticalScrollbars;
     if (OwnPtr<WebScrollbarLayer> scrollbarLayer = scrollbars.take(scrollableArea))
         GraphicsLayer::unregisterContentsLayer(scrollbarLayer->layer());
 }
 
-static PassOwnPtr<WebScrollbarLayer> createScrollbarLayer(Scrollbar* scrollbar, float deviceScaleFactor)
+static PassOwnPtr<WebScrollbarLayer> createScrollbarLayer(Scrollbar& scrollbar, float deviceScaleFactor)
 {
-    ScrollbarTheme* theme = scrollbar->theme();
+    ScrollbarTheme& theme = scrollbar.theme();
     WebScrollbarThemePainter painter(theme, scrollbar, deviceScaleFactor);
     OwnPtr<WebScrollbarThemeGeometry> geometry(WebScrollbarThemeGeometryNative::create(theme));
 
-    OwnPtr<WebScrollbarLayer> scrollbarLayer = adoptPtr(Platform::current()->compositorSupport()->createScrollbarLayer(WebScrollbarImpl::create(scrollbar), painter, geometry.leakPtr()));
+    OwnPtr<WebScrollbarLayer> scrollbarLayer = adoptPtr(Platform::current()->compositorSupport()->createScrollbarLayer(WebScrollbarImpl::create(&scrollbar), painter, geometry.leakPtr()));
     GraphicsLayer::registerContentsLayer(scrollbarLayer->layer());
     return scrollbarLayer.release();
 }
 
 PassOwnPtr<WebScrollbarLayer> ScrollingCoordinator::createSolidColorScrollbarLayer(ScrollbarOrientation orientation, int thumbThickness, int trackStart, bool isLeftSideVerticalScrollbar)
 {
     WebScrollbar::Orientation webOrientation = (orientation == HorizontalScrollbar) ? WebScrollbar::Horizontal : WebScrollbar::Vertical;
     OwnPtr<WebScrollbarLayer> scrollbarLayer = adoptPtr(Platform::current()->compositorSupport()->createSolidColorScrollbarLayer(webOrientation, thumbThickness, trackStart, isLeftSideVerticalScrollbar));
     GraphicsLayer::registerContentsLayer(scrollbarLayer->layer());
     return scrollbarLayer.release();
@@ skipping 49 matching lines @@
 
     if (!platformSupportsCoordinatedScrollbar) {
         if (scrollbarGraphicsLayer) {
             WebLayer* scrollbarLayer = toWebLayer(scrollbarGraphicsLayer);
             scrollbarLayer->setShouldScrollOnMainThread(true);
         }
         return;
     }
 
     if (scrollbarGraphicsLayer) {
-        Scrollbar* scrollbar = orientation == HorizontalScrollbar ? scrollableArea->horizontalScrollbar() : scrollableArea->verticalScrollbar();
-        if (scrollbar->isCustomScrollbar()) {
+        Scrollbar& scrollbar = orientation == HorizontalScrollbar ? *scrollableArea->horizontalScrollbar() : *scrollableArea->verticalScrollbar();
+        if (scrollbar.isCustomScrollbar()) {
             detachScrollbarLayer(scrollbarGraphicsLayer);
             return;
         }
 
         WebScrollbarLayer* scrollbarLayer = getWebScrollbarLayer(scrollableArea, orientation);
         if (!scrollbarLayer) {
             Settings* settings = m_page->mainFrame()->settings();
 
             OwnPtr<WebScrollbarLayer> webScrollbarLayer;
             if (settings->useSolidColorScrollbars()) {
                 ASSERT(RuntimeEnabledFeatures::overlayScrollbarsEnabled());
-                webScrollbarLayer = createSolidColorScrollbarLayer(orientation, scrollbar->theme()->thumbThickness(scrollbar), scrollbar->theme()->trackPosition(scrollbar), scrollableArea->shouldPlaceVerticalScrollbarOnLeft());
+                webScrollbarLayer = createSolidColorScrollbarLayer(orientation, scrollbar.theme().thumbThickness(scrollbar), scrollbar.theme().trackPosition(scrollbar), scrollableArea->shouldPlaceVerticalScrollbarOnLeft());
             } else {
                 webScrollbarLayer = createScrollbarLayer(scrollbar, m_page->deviceScaleFactor());
             }
             scrollbarLayer = addWebScrollbarLayer(scrollableArea, orientation, webScrollbarLayer.release());
         }
 
         WebLayer* scrollLayer = toWebLayer(scrollableArea->layerForScrolling());
         setupScrollbarLayer(scrollbarGraphicsLayer, scrollbarLayer, scrollLayer);
 
         // Root layer non-overlay scrollbars should be marked opaque to disable
         // blending.
-        bool isOpaqueScrollbar = !scrollbar->isOverlayScrollbar();
+        bool isOpaqueScrollbar = !scrollbar.isOverlayScrollbar();
         scrollbarGraphicsLayer->setContentsOpaque(isMainFrame && isOpaqueScrollbar);
     } else
         removeWebScrollbarLayer(scrollableArea, orientation);
 }
 
 bool ScrollingCoordinator::scrollableAreaScrollLayerDidChange(ScrollableArea* scrollableArea)
 {
     GraphicsLayer* scrollLayer = scrollableArea->layerForScrolling();
 
     if (scrollLayer) {
@@ skipping 584 matching lines @@
 {
     ASSERT(isMainThread());
 
     if (!m_page)
         return;
 
     FrameView* frameView = m_page->deprecatedLocalMainFrame()->view();
     if (!frameView)
         return;
 
-    frameView->scrollAnimator()->handleWheelEventPhase(phase);
+    frameView->scrollAnimator().handleWheelEventPhase(phase);
 }
 #endif
 
 bool ScrollingCoordinator::hasVisibleSlowRepaintViewportConstrainedObjects(FrameView* frameView) const
 {
     const FrameView::ViewportConstrainedObjectSet* viewportConstrainedObjects = frameView->viewportConstrainedObjects();
     if (!viewportConstrainedObjects)
         return false;
 
     for (const LayoutObject* layoutObject : *viewportConstrainedObjects) {
@@ skipping 83 matching lines @@
     bool frameIsScrollable = frameView && frameView->isScrollable();
     if (frameIsScrollable != m_wasFrameScrollable)
         return true;
 
     if (WebLayer* scrollLayer = frameView ? toWebLayer(frameView->layerForScrolling()) : nullptr)
         return WebSize(frameView->contentsSize()) != scrollLayer->bounds();
     return false;
 }
 
 } // namespace blink