Refactor DrawingRecorders to check for cached drawings earlier

Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 68 matching lines @@
     updateEnabledState(scrollbar);
     updateScrollbarOverlayStyle(scrollbar);
 }
 
 ScrollbarPainter ScrollbarThemeMacOverlayAPI::painterForScrollbar(ScrollbarThemeClient* scrollbar)
 {
     return scrollbarPainterMap()->get(scrollbar).get();
 }
 
 void ScrollbarThemeMacOverlayAPI::paintTrackBackground(GraphicsContext* context, ScrollbarThemeClient* scrollbar, const IntRect& rect) {
+    if (DrawingRecorder::useCachedDrawingIfPossible(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground))
+        return;
+
     DrawingRecorder recorder(*context, *scrollbar, DisplayItem::ScrollbarTrackBackground, rect);
-    if (recorder.canUseCachedDrawing())
-        return;
 
     ASSERT(isOverlayAPIAvailable());
 
     GraphicsContextStateSaver stateSaver(*context);
     context->translate(rect.x(), rect.y());
     LocalCurrentGraphicsContext localContext(context, IntRect(IntPoint(), rect.size()));
 
     CGRect frameRect = scrollbar->frameRect();
     ScrollbarPainter scrollbarPainter = painterForScrollbar(scrollbar);
     [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, 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);
-    if (recorder.canUseCachedDrawing())
-        return;
 
     ASSERT(isOverlayAPIAvailable());
 
     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 setBoundsSize:NSSizeFromCGSize(rect.size())];
@@ skipping 74 matching lines @@
 {
     return [painterForScrollbar(scrollbar) knobMinLength];
 }
 
 void ScrollbarThemeMacOverlayAPI::updateEnabledState(ScrollbarThemeClient* scrollbar)
 {
     [painterForScrollbar(scrollbar) setEnabled:scrollbar->enabled()];
 }
 
 } // namespace blink