Refactor DrawingRecorders to check for cached drawings earlier

Source/platform/scroll/ScrollbarThemeMock.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 34 matching lines @@
     return cScrollbarThickness[controlSize];
 }
 
 bool ScrollbarThemeMock::usesOverlayScrollbars() const
 {
     return RuntimeEnabledFeatures::overlayScrollbarsEnabled();
 }
 
 void ScrollbarThemeMock::paintTrackBackground(GraphicsContext* context, ScrollbarThemeClient* scrollbar, const IntRect& trackRect)
 {
+    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground))
+        return;
+
     DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground, trackRect);
-    if (recorder.canUseCachedDrawing())
-        return;
     context->fillRect(trackRect, scrollbar->enabled() ? Color::lightGray : Color(0xFFE0E0E0));
 }
 
 void ScrollbarThemeMock::paintThumb(GraphicsContext* context, ScrollbarThemeClient* scrollbar, const IntRect& thumbRect)
 {
-    if (scrollbar->enabled()) {
-        DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarThumb, thumbRect);
-        if (recorder.canUseCachedDrawing())
-            return;
-        context->fillRect(thumbRect, Color::darkGray);
-    }
+    if (!scrollbar->enabled())
+        return;
+
+    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarThumb))
+        return;
+
+    DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarThumb, thumbRect);
+    context->fillRect(thumbRect, Color::darkGray);
 }
 
 }