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

third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm

Index: third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm b/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
index 91d5131b11a9dee30de83fbc5ad6940b13562e22..45df5b185689c2c858b445a0d2596966e1ca2e97 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
+++ b/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
@@ -92,10 +92,10 @@ namespace blink {
 
 typedef HashMap<ScrollbarThemeClient*, RetainPtr<WebCoreScrollbarObserver> > ScrollbarPainterMap;
 
-static ScrollbarPainterMap* scrollbarPainterMap()
+static ScrollbarPainterMap& scrollbarPainterMap()
 {
     static ScrollbarPainterMap* map = new ScrollbarPainterMap;
-    return map;
+    return *map;
 }
 
 static bool supportsExpandedScrollbars()
@@ -105,76 +105,76 @@ static bool supportsExpandedScrollbars()
     return globalSupportsExpandedScrollbars;
 }
 
-void ScrollbarThemeMacOverlayAPI::registerScrollbar(ScrollbarThemeClient* scrollbar)
+void ScrollbarThemeMacOverlayAPI::registerScrollbar(ScrollbarThemeClient& scrollbar)
 {
     ScrollbarThemeMacCommon::registerScrollbar(scrollbar);
 
-    bool isHorizontal = scrollbar->orientation() == HorizontalScrollbar;
-    ScrollbarPainter scrollbarPainter = [NSClassFromString(@"NSScrollerImp") scrollerImpWithStyle:recommendedScrollerStyle() controlSize:(NSControlSize)scrollbar->controlSize() horizontal:isHorizontal replacingScrollerImp:nil];
-    RetainPtr<WebCoreScrollbarObserver> observer = [[WebCoreScrollbarObserver alloc] initWithScrollbar:scrollbar painter:scrollbarPainter];
+    bool isHorizontal = scrollbar.orientation() == HorizontalScrollbar;
+    ScrollbarPainter scrollbarPainter = [NSClassFromString(@"NSScrollerImp") scrollerImpWithStyle:recommendedScrollerStyle() controlSize:(NSControlSize)scrollbar.controlSize() horizontal:isHorizontal replacingScrollerImp:nil];
+    RetainPtr<WebCoreScrollbarObserver> observer = [[WebCoreScrollbarObserver alloc] initWithScrollbar:&scrollbar painter:scrollbarPainter];
 
-    scrollbarPainterMap()->add(scrollbar, observer);
+    scrollbarPainterMap().add(&scrollbar, observer);
     updateEnabledState(scrollbar);
     updateScrollbarOverlayStyle(scrollbar);
 }
 
-void ScrollbarThemeMacOverlayAPI::unregisterScrollbar(ScrollbarThemeClient* scrollbar)
+void ScrollbarThemeMacOverlayAPI::unregisterScrollbar(ScrollbarThemeClient& scrollbar)
 {
-    scrollbarPainterMap()->remove(scrollbar);
+    scrollbarPainterMap().remove(&scrollbar);
 
     ScrollbarThemeMacCommon::unregisterScrollbar(scrollbar);
 }
 
-void ScrollbarThemeMacOverlayAPI::setNewPainterForScrollbar(ScrollbarThemeClient* scrollbar, ScrollbarPainter newPainter)
+void ScrollbarThemeMacOverlayAPI::setNewPainterForScrollbar(ScrollbarThemeClient& scrollbar, ScrollbarPainter newPainter)
 {
-    RetainPtr<WebCoreScrollbarObserver> observer = [[WebCoreScrollbarObserver alloc] initWithScrollbar:scrollbar painter:newPainter];
-    scrollbarPainterMap()->set(scrollbar, observer);
+    RetainPtr<WebCoreScrollbarObserver> observer = [[WebCoreScrollbarObserver alloc] initWithScrollbar:&scrollbar painter:newPainter];
+    scrollbarPainterMap().set(&scrollbar, observer);
     updateEnabledState(scrollbar);
     updateScrollbarOverlayStyle(scrollbar);
 }
 
-ScrollbarPainter ScrollbarThemeMacOverlayAPI::painterForScrollbar(const ScrollbarThemeClient* scrollbar) const
+ScrollbarPainter ScrollbarThemeMacOverlayAPI::painterForScrollbar(const ScrollbarThemeClient& scrollbar) const
 {
-    return [scrollbarPainterMap()->get(const_cast<ScrollbarThemeClient*>(scrollbar)).get() painter];
+    return [scrollbarPainterMap().get(const_cast<ScrollbarThemeClient*>(&scrollbar)).get() painter];
 }
 
-void ScrollbarThemeMacOverlayAPI::paintTrackBackground(GraphicsContext* context, const ScrollbarThemeClient* scrollbar, const IntRect& rect) {
-    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground))
+void ScrollbarThemeMacOverlayAPI::paintTrackBackground(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect) {
+    if (DrawingRecorder::useCachedDrawingIfPossible(context, scrollbar, DisplayItem::ScrollbarTrackBackground))
         return;
 
-    DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground, rect);
+    DrawingRecorder recorder(context, scrollbar, DisplayItem::ScrollbarTrackBackground, rect);
 
     ASSERT(isOverlayAPIAvailable());
 
-    GraphicsContextStateSaver stateSaver(*context);
-    context->translate(rect.x(), rect.y());
-    LocalCurrentGraphicsContext localContext(context, IntRect(IntPoint(), rect.size()));
+    GraphicsContextStateSaver stateSaver(context);
+    context.translate(rect.x(), rect.y());
+    LocalCurrentGraphicsContext localContext(&context, IntRect(IntPoint(), rect.size()));
 
-    CGRect frameRect = scrollbar->frameRect();
+    CGRect frameRect = scrollbar.frameRect();
     ScrollbarPainter scrollbarPainter = painterForScrollbar(scrollbar);
-    [scrollbarPainter setEnabled:scrollbar->enabled()];
+    [scrollbarPainter setEnabled:scrollbar.enabled()];
     [scrollbarPainter setBoundsSize: NSSizeFromCGSize(frameRect.size)];
     NSRect trackRect = NSMakeRect(0, 0, frameRect.size.width, frameRect.size.height);
     [scrollbarPainter drawKnobSlotInRect:trackRect highlight:NO];
 }
 
-void ScrollbarThemeMacOverlayAPI::paintThumb(GraphicsContext* context, const ScrollbarThemeClient* scrollbar, const IntRect& rect) {
-    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarThumb))
+void ScrollbarThemeMacOverlayAPI::paintThumb(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect) {
+    if (DrawingRecorder::useCachedDrawingIfPossible(context, scrollbar, DisplayItem::ScrollbarThumb))
         return;
 
     // Expand dirty rect to allow for scroll thumb anti-aliasing in minimum thumb size case.
     IntRect dirtyRect = IntRect(rect);
     dirtyRect.inflate(1);
-    DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarThumb, dirtyRect);
+    DrawingRecorder recorder(context, scrollbar, DisplayItem::ScrollbarThumb, dirtyRect);
 
     ASSERT(isOverlayAPIAvailable());
 
-    GraphicsContextStateSaver stateSaver(*context);
-    context->translate(rect.x(), rect.y());
-    LocalCurrentGraphicsContext localContext(context, IntRect(IntPoint(), rect.size()));
+    GraphicsContextStateSaver stateSaver(context);
+    context.translate(rect.x(), rect.y());
+    LocalCurrentGraphicsContext localContext(&context, IntRect(IntPoint(), rect.size()));
 
     ScrollbarPainter scrollbarPainter = painterForScrollbar(scrollbar);
-    [scrollbarPainter setEnabled:scrollbar->enabled()];
+    [scrollbarPainter setEnabled:scrollbar.enabled()];
     [scrollbarPainter setBoundsSize:NSSizeFromCGSize(rect.size())];
     [scrollbarPainter setDoubleValue:0];
     [scrollbarPainter setKnobProportion:1];
@@ -182,12 +182,12 @@ void ScrollbarThemeMacOverlayAPI::paintThumb(GraphicsContext* context, const Scr
     CGFloat oldKnobAlpha = [scrollbarPainter knobAlpha];
     [scrollbarPainter setKnobAlpha:1];
 
-    if (scrollbar->enabled())
+    if (scrollbar.enabled())
         [scrollbarPainter drawKnob];
 
     // If this state is not set, then moving the cursor over the scrollbar area will only cause the
     // scrollbar to engorge when moved over the top of the scrollbar area.
-    [scrollbarPainter setBoundsSize: NSSizeFromCGSize(scrollbar->frameRect().size())];
+    [scrollbarPainter setBoundsSize: NSSizeFromCGSize(scrollbar.frameRect().size())];
     [scrollbarPainter setKnobAlpha:oldKnobAlpha];
 }
 
@@ -211,10 +211,10 @@ bool ScrollbarThemeMacOverlayAPI::usesOverlayScrollbars() const
     return recommendedScrollerStyle() == NSScrollerStyleOverlay;
 }
 
-void ScrollbarThemeMacOverlayAPI::updateScrollbarOverlayStyle(const ScrollbarThemeClient* scrollbar)
+void ScrollbarThemeMacOverlayAPI::updateScrollbarOverlayStyle(const ScrollbarThemeClient& scrollbar)
 {
     ScrollbarPainter painter = painterForScrollbar(scrollbar);
-    switch (scrollbar->scrollbarOverlayStyle()) {
+    switch (scrollbar.scrollbarOverlayStyle()) {
     case ScrollbarOverlayStyleDefault:
         [painter setKnobStyle:NSScrollerKnobStyleDefault];
         break;
@@ -232,45 +232,45 @@ ScrollbarButtonsPlacement ScrollbarThemeMacOverlayAPI::buttonsPlacement() const
     return ScrollbarButtonsPlacementNone;
 }
 
-bool ScrollbarThemeMacOverlayAPI::hasThumb(const ScrollbarThemeClient* scrollbar)
+bool ScrollbarThemeMacOverlayAPI::hasThumb(const ScrollbarThemeClient& scrollbar)
 {
     ScrollbarPainter painter = painterForScrollbar(scrollbar);
     int minLengthForThumb = [painter knobMinLength] + [painter trackOverlapEndInset] + [painter knobOverlapEndInset]
         + 2 * ([painter trackEndInset] + [painter knobEndInset]);
-    return scrollbar->enabled() && (scrollbar->orientation() == HorizontalScrollbar ?
-             scrollbar->width() :
-             scrollbar->height()) >= minLengthForThumb;
+    return scrollbar.enabled() && (scrollbar.orientation() == HorizontalScrollbar ?
+             scrollbar.width() :
+             scrollbar.height()) >= minLengthForThumb;
 }
 
-IntRect ScrollbarThemeMacOverlayAPI::backButtonRect(const ScrollbarThemeClient* scrollbar, ScrollbarPart part, bool painting)
+IntRect ScrollbarThemeMacOverlayAPI::backButtonRect(const ScrollbarThemeClient& scrollbar, ScrollbarPart part, bool painting)
 {
     ASSERT(buttonsPlacement() == ScrollbarButtonsPlacementNone);
     return IntRect();
 }
 
-IntRect ScrollbarThemeMacOverlayAPI::forwardButtonRect(const ScrollbarThemeClient* scrollbar, ScrollbarPart part, bool painting)
+IntRect ScrollbarThemeMacOverlayAPI::forwardButtonRect(const ScrollbarThemeClient& scrollbar, ScrollbarPart part, bool painting)
 {
     ASSERT(buttonsPlacement() == ScrollbarButtonsPlacementNone);
     return IntRect();
 }
 
-IntRect ScrollbarThemeMacOverlayAPI::trackRect(const ScrollbarThemeClient* scrollbar, bool painting)
+IntRect ScrollbarThemeMacOverlayAPI::trackRect(const ScrollbarThemeClient& scrollbar, bool painting)
 {
     ASSERT(!hasButtons(scrollbar));
-    return scrollbar->frameRect();
+    return scrollbar.frameRect();
 }
 
-int ScrollbarThemeMacOverlayAPI::minimumThumbLength(const ScrollbarThemeClient* scrollbar)
+int ScrollbarThemeMacOverlayAPI::minimumThumbLength(const ScrollbarThemeClient& scrollbar)
 {
     return [painterForScrollbar(scrollbar) knobMinLength];
 }
 
-void ScrollbarThemeMacOverlayAPI::updateEnabledState(const ScrollbarThemeClient* scrollbar)
+void ScrollbarThemeMacOverlayAPI::updateEnabledState(const ScrollbarThemeClient& scrollbar)
 {
-    [painterForScrollbar(scrollbar) setEnabled:scrollbar->enabled()];
+    [painterForScrollbar(scrollbar) setEnabled:scrollbar.enabled()];
 }
 
-float ScrollbarThemeMacOverlayAPI::thumbOpacity(const ScrollbarThemeClient* scrollbar) const {
+float ScrollbarThemeMacOverlayAPI::thumbOpacity(const ScrollbarThemeClient& scrollbar) const {
     ScrollbarPainter scrollbarPainter = painterForScrollbar(scrollbar);
     return [scrollbarPainter knobAlpha];
 }