Use DrawingRecorder::canUseCachedDrawing

Source/core/paint/BoxPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/BoxPainter.h"
 
 #include "core/HTMLNames.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLFrameOwnerElement.h"
@@ skipping 51 matching lines @@
             bounds = m_renderBox.visualOverflowRect();
             bounds.moveBy(paintOffset);
             bounds = pixelSnappedIntRect(bounds);
         }
     }
     return bounds;
 }
 
 void BoxPainter::paintBoxDecorationBackgroundWithRect(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, const LayoutRect& paintRect)
 {
+    RenderDrawingRecorder recorder(paintInfo.context, m_renderBox, paintInfo.phase, boundsForDrawingRecorder(paintOffset));
+    if (recorder.canUseCachedDrawing())
+        return;
+
     RenderStyle* style = m_renderBox.style();
     BoxDecorationData boxDecorationData(*style, m_renderBox.canRenderBorderImage(), m_renderBox.backgroundHasOpaqueTopLayer(), m_renderBox.backgroundShouldAlwaysBeClipped(), paintInfo.context);
 
-    RenderDrawingRecorder recorder(paintInfo.context, &m_renderBox, paintInfo.phase, boundsForDrawingRecorder(paintOffset));
-
     // FIXME: Should eventually give the theme control over whether the box shadow should paint, since controls could have
     // custom shadows of their own.
     if (!m_renderBox.boxShadowShouldBeAppliedToBackground(boxDecorationData.bleedAvoidance()))
         paintBoxShadow(paintInfo, paintRect, style, Normal);
 
     GraphicsContextStateSaver stateSaver(*paintInfo.context, false);
     if (boxDecorationData.bleedAvoidance() == BackgroundBleedClipBackground) {
         stateSaver.save();
         RoundedRect border = style->getRoundedBorderFor(paintRect);
         paintInfo.context->clipRoundedRect(border);
@@ skipping 2084 matching lines @@
 
     FloatPoint secondQuad[4];
     secondQuad[0] = quad[0];
     secondQuad[1] = FloatPoint(quad[0].x() - r1 * cx, quad[0].y() - r1 * cy);
     secondQuad[2] = quad[2];
     secondQuad[3] = quad[3];
     graphicsContext->clipPolygon(4, secondQuad, !secondEdgeMatches);
 }
 
 } // namespace blink