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

third_party/WebKit/Source/platform/scroll/ScrollbarThemeMock.cpp

Index: third_party/WebKit/Source/platform/scroll/ScrollbarThemeMock.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMock.cpp b/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMock.cpp
index 4007cbb6655e4ff942f4ac47e0c4a8f342b44e58..8a7d2d9d050c61805088827925fd1d6ef53db1de 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMock.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMock.cpp
@@ -57,31 +57,30 @@ bool ScrollbarThemeMock::shouldRepaintAllPartsOnInvalidation() const
     return gShouldRepaintAllPartsOnInvalidation;
 }
 
-IntRect ScrollbarThemeMock::trackRect(const ScrollbarThemeClient* scrollbar, bool)
+IntRect ScrollbarThemeMock::trackRect(const ScrollbarThemeClient& scrollbar, bool)
 {
-    return scrollbar->frameRect();
+    return scrollbar.frameRect();
 }
 
-
-void ScrollbarThemeMock::paintTrackBackground(GraphicsContext* context, const ScrollbarThemeClient* scrollbar, const IntRect& trackRect)
+void ScrollbarThemeMock::paintTrackBackground(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& trackRect)
 {
-    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground))
+    if (DrawingRecorder::useCachedDrawingIfPossible(context, scrollbar, DisplayItem::ScrollbarTrackBackground))
         return;
 
-    DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground, trackRect);
-    context->fillRect(trackRect, scrollbar->enabled() ? Color::lightGray : Color(0xFFE0E0E0));
+    DrawingRecorder recorder(context, scrollbar, DisplayItem::ScrollbarTrackBackground, trackRect);
+    context.fillRect(trackRect, scrollbar.enabled() ? Color::lightGray : Color(0xFFE0E0E0));
 }
 
-void ScrollbarThemeMock::paintThumb(GraphicsContext* context, const ScrollbarThemeClient* scrollbar, const IntRect& thumbRect)
+void ScrollbarThemeMock::paintThumb(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& thumbRect)
 {
-    if (!scrollbar->enabled())
+    if (!scrollbar.enabled())
         return;
 
-    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarThumb))
+    if (DrawingRecorder::useCachedDrawingIfPossible(context, scrollbar, DisplayItem::ScrollbarThumb))
         return;
 
-    DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarThumb, thumbRect);
-    context->fillRect(thumbRect, Color::darkGray);
+    DrawingRecorder recorder(context, scrollbar, DisplayItem::ScrollbarThumb, thumbRect);
+    context.fillRect(thumbRect, Color::darkGray);
 }
 
 }