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

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

Index: third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
diff --git a/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp b/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
index e7e5e5869e1158b80f7bcddde49d5b2069947ba8..9d5161debbaf8df35c0d66b5dc6aa74dc906b3ad 100644
--- a/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
+++ b/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
@@ -276,13 +276,13 @@ void ScrollingCoordinator::removeWebScrollbarLayer(ScrollableArea* scrollableAre
         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();
 }
@@ -352,8 +352,8 @@ void ScrollingCoordinator::scrollableAreaScrollbarLayerDidChange(ScrollableArea*
     }
 
     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;
         }
@@ -365,7 +365,7 @@ void ScrollingCoordinator::scrollableAreaScrollbarLayerDidChange(ScrollableArea*
             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());
             }
@@ -377,7 +377,7 @@ void ScrollingCoordinator::scrollableAreaScrollbarLayerDidChange(ScrollableArea*
 
         // 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);
@@ -982,7 +982,7 @@ void ScrollingCoordinator::handleWheelEventPhase(PlatformWheelEventPhase phase)
     if (!frameView)
         return;
 
-    frameView->scrollAnimator()->handleWheelEventPhase(phase);
+    frameView->scrollAnimator().handleWheelEventPhase(phase);
 }
 #endif