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

third_party/WebKit/Source/platform/scroll/ScrollableArea.h

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
index d643a1a87451842f0d6bd3a69075080dc07a77f7..e8b1928c208eed82b906a481a1571b3cceb7636f 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
@@ -106,15 +106,15 @@ public:
     void mouseEnteredContentArea() const;
     void mouseExitedContentArea() const;
     void mouseMovedInContentArea() const;
-    void mouseEnteredScrollbar(Scrollbar*) const;
-    void mouseExitedScrollbar(Scrollbar*) const;
+    void mouseEnteredScrollbar(Scrollbar&) const;
+    void mouseExitedScrollbar(Scrollbar&) const;
     void contentAreaDidShow() const;
     void contentAreaDidHide() const;
 
     void finishCurrentScrollAnimations() const;
 
-    virtual void didAddScrollbar(Scrollbar*, ScrollbarOrientation);
-    virtual void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation);
+    virtual void didAddScrollbar(Scrollbar&, ScrollbarOrientation);
+    virtual void willRemoveScrollbar(Scrollbar&, ScrollbarOrientation);
 
     virtual void contentsResized();
 
@@ -123,12 +123,12 @@ public:
     ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); }
 
     // This getter will create a ScrollAnimatorBase if it doesn't already exist.
-    ScrollAnimatorBase* scrollAnimator() const;
+    ScrollAnimatorBase& scrollAnimator() const;
 
     // This getter will return null if the ScrollAnimatorBase hasn't been created yet.
     ScrollAnimatorBase* existingScrollAnimator() const { return m_scrollAnimator.get(); }
 
-    ProgrammaticScrollAnimator* programmaticScrollAnimator() const;
+    ProgrammaticScrollAnimator& programmaticScrollAnimator() const;
     ProgrammaticScrollAnimator* existingProgrammaticScrollAnimator() const { return m_programmaticScrollAnimator.get(); }
 
     const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
@@ -144,7 +144,7 @@ public:
 
     virtual bool isActive() const = 0;
     virtual int scrollSize(ScrollbarOrientation) const = 0;
-    void setScrollbarNeedsPaintInvalidation(Scrollbar*);
+    void setScrollbarNeedsPaintInvalidation(ScrollbarOrientation);
     virtual bool isScrollCornerVisible() const = 0;
     virtual IntRect scrollCornerRect() const = 0;
     void setScrollCornerNeedsPaintInvalidation();
@@ -153,25 +153,25 @@ public:
     // Convert points and rects between the scrollbar and its containing Widget.
     // The client needs to implement these in order to be aware of layout effects
     // like CSS transforms.
-    virtual IntRect convertFromScrollbarToContainingWidget(const Scrollbar* scrollbar, const IntRect& scrollbarRect) const
+    virtual IntRect convertFromScrollbarToContainingWidget(const Scrollbar& scrollbar, const IntRect& scrollbarRect) const
     {
-        return scrollbar->Widget::convertToContainingWidget(scrollbarRect);
+        return scrollbar.Widget::convertToContainingWidget(scrollbarRect);
     }
-    virtual IntRect convertFromContainingWidgetToScrollbar(const Scrollbar* scrollbar, const IntRect& parentRect) const
+    virtual IntRect convertFromContainingWidgetToScrollbar(const Scrollbar& scrollbar, const IntRect& parentRect) const
     {
-        return scrollbar->Widget::convertFromContainingWidget(parentRect);
+        return scrollbar.Widget::convertFromContainingWidget(parentRect);
     }
-    virtual IntPoint convertFromScrollbarToContainingWidget(const Scrollbar* scrollbar, const IntPoint& scrollbarPoint) const
+    virtual IntPoint convertFromScrollbarToContainingWidget(const Scrollbar& scrollbar, const IntPoint& scrollbarPoint) const
     {
-        return scrollbar->Widget::convertToContainingWidget(scrollbarPoint);
+        return scrollbar.Widget::convertToContainingWidget(scrollbarPoint);
     }
-    virtual IntPoint convertFromContainingWidgetToScrollbar(const Scrollbar* scrollbar, const IntPoint& parentPoint) const
+    virtual IntPoint convertFromContainingWidgetToScrollbar(const Scrollbar& scrollbar, const IntPoint& parentPoint) const
     {
-        return scrollbar->Widget::convertFromContainingWidget(parentPoint);
+        return scrollbar.Widget::convertFromContainingWidget(parentPoint);
     }
 
-    virtual Scrollbar* horizontalScrollbar() const { return 0; }
-    virtual Scrollbar* verticalScrollbar() const { return 0; }
+    virtual Scrollbar* horizontalScrollbar() const { return nullptr; }
+    virtual Scrollbar* verticalScrollbar() const { return nullptr; }
 
     // scrollPosition is relative to the scrollOrigin. i.e. If the page is RTL
     // then scrollPosition will be negative. By default, scrollPositionDouble()