Refactor DrawingRecorders to check for cached drawings earlier

Source/platform/scroll/ScrollbarThemeAura.cpp

 /*
  * Copyright (c) 2008, 2009, 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 54 matching lines @@
     // Horiz and Vert scrollbars are the same thickness.
     // In unit tests we don't have the mock theme engine (because of layering violations), so we hard code the size (see bug 327470).
     if (useMockTheme())
         return 15;
     IntSize scrollbarSize = Platform::current()->themeEngine()->getSize(WebThemeEngine::PartScrollbarVerticalTrack);
     return scrollbarSize.width();
 }
 
 void ScrollbarThemeAura::paintTrackPiece(GraphicsContext* gc, ScrollbarThemeClient* scrollbar, const IntRect& rect, ScrollbarPart partType)
 {
+    DisplayItem::Type displayItemType = trackPiecePartToDisplayItemType(partType);
+    if (DrawingRecorder::useCachedDrawingIfPossible(*gc, *scrollbar, displayItemType))
+        return;
+
+    DrawingRecorder recorder(*gc, *scrollbar, displayItemType, rect);
+
     WebThemeEngine::State state = scrollbar->hoveredPart() == partType ? WebThemeEngine::StateHover : WebThemeEngine::StateNormal;
 
     if (useMockTheme() && !scrollbar->enabled())
         state = WebThemeEngine::StateDisabled;
 
-    DrawingRecorder recorder(*gc, *scrollbar, trackPiecePartToDisplayItemType(partType), rect);
-    if (recorder.canUseCachedDrawing())
-        return;
-
     IntRect alignRect = trackRect(scrollbar, false);
     WebThemeEngine::ExtraParams extraParams;
     extraParams.scrollbarTrack.isBack = (partType == BackTrackPart);
     extraParams.scrollbarTrack.trackX = alignRect.x();
     extraParams.scrollbarTrack.trackY = alignRect.y();
     extraParams.scrollbarTrack.trackWidth = alignRect.width();
     extraParams.scrollbarTrack.trackHeight = alignRect.height();
     Platform::current()->themeEngine()->paint(gc->canvas(), scrollbar->orientation() == HorizontalScrollbar ? WebThemeEngine::PartScrollbarHorizontalTrack : WebThemeEngine::PartScrollbarVerticalTrack, state, WebRect(rect), &extraParams);
 }
 
@@ skipping 19 matching lines @@
             paintPart = WebThemeEngine::PartScrollbarUpArrow;
             checkMin = true;
         } else if (useMockTheme() && part != ForwardButtonEndPart) {
             return;
         } else {
             paintPart = WebThemeEngine::PartScrollbarDownArrow;
             checkMax = true;
         }
     }
 
-    DrawingRecorder recorder(*gc, *scrollbar, buttonPartToDisplayItemType(part), rect);
-    if (recorder.canUseCachedDrawing())
+    DisplayItem::Type displayItemType = buttonPartToDisplayItemType(part);
+    if (DrawingRecorder::useCachedDrawingIfPossible(*gc, *scrollbar, displayItemType))
         return;
 
+    DrawingRecorder recorder(*gc, *scrollbar, displayItemType, rect);
+
     if (useMockTheme() && !scrollbar->enabled()) {
         state = WebThemeEngine::StateDisabled;
     } else if (!useMockTheme() && ((checkMin && (scrollbar->currentPos() <= 0))
         || (checkMax && scrollbar->currentPos() >= scrollbar->maximum()))) {
         state = WebThemeEngine::StateDisabled;
     } else {
         if (part == scrollbar->pressedPart())
             state = WebThemeEngine::StatePressed;
         else if (part == scrollbar->hoveredPart())
             state = WebThemeEngine::StateHover;
     }
     Platform::current()->themeEngine()->paint(gc->canvas(), paintPart, state, WebRect(rect), 0);
 }
 
 void ScrollbarThemeAura::paintThumb(GraphicsContext* gc, ScrollbarThemeClient* scrollbar, const IntRect& rect)
 {
+    if (DrawingRecorder::useCachedDrawingIfPossible(*gc, *scrollbar, DisplayItem::ScrollbarThumb))
+        return;
+
     DrawingRecorder recorder(*gc, *scrollbar, DisplayItem::ScrollbarThumb, rect);
-    if (recorder.canUseCachedDrawing())
-        return;
 
     WebThemeEngine::State state;
     WebCanvas* canvas = gc->canvas();
     if (scrollbar->pressedPart() == ThumbPart)
         state = WebThemeEngine::StatePressed;
     else if (scrollbar->hoveredPart() == ThumbPart)
         state = WebThemeEngine::StateHover;
     else
         state = WebThemeEngine::StateNormal;
     Platform::current()->themeEngine()->paint(canvas, scrollbar->orientation() == HorizontalScrollbar ? WebThemeEngine::PartScrollbarHorizontalThumb : WebThemeEngine::PartScrollbarVerticalThumb, state, WebRect(rect), 0);
@@ skipping 16 matching lines @@
     if (scrollbar->orientation() == VerticalScrollbar) {
         IntSize size = Platform::current()->themeEngine()->getSize(WebThemeEngine::PartScrollbarVerticalThumb);
         return size.height();
     }
 
     IntSize size = Platform::current()->themeEngine()->getSize(WebThemeEngine::PartScrollbarHorizontalThumb);
     return size.width();
 }
 
 } // namespace blink