Allocate a drawing recorder locally to BoxPainter code in the mask phase.

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 501 matching lines @@
             obj.paint(info, scrolledPaintRect.location() - localOffset);
         }
 
         context->endLayer();
         context->endLayer();
     }
 }
 
 void BoxPainter::paintMask(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
+    LayoutRect visualOverflowRect(m_layoutBox.visualOverflowRect());
+    visualOverflowRect.moveBy(paintOffset);
+
+    LayoutObjectDrawingRecorder recorder(*paintInfo.context, m_layoutBox, paintInfo.phase, visualOverflowRect);
+    if (recorder.canUseCachedDrawing())

[wkorman, 2015/06/19 23:20:43]

Could also just add this to the three bail-out conditionals we've already got on
line 528 but perhaps having separate is clearer, fine either way.

[chrishtr, 2015/06/20 02:22:45]

I prefer separate, to make it clear we are checking for caching.

+        return;
     if (!paintInfo.shouldPaintWithinRoot(&m_layoutBox) || m_layoutBox.style()->visibility() != VISIBLE || paintInfo.phase != PaintPhaseMask)
         return;
-
     LayoutRect paintRect = LayoutRect(paintOffset, m_layoutBox.size());
     paintMaskImages(paintInfo, paintRect);
 }
 
 void BoxPainter::paintMaskImages(const PaintInfo& paintInfo, const LayoutRect& paintRect)
 {
     // Figure out if we need to push a transparency layer to render our mask.
     bool pushTransparencyLayer = false;
     bool compositedMask = m_layoutBox.hasLayer() && m_layoutBox.layer()->hasCompositedMask();
     bool flattenCompositingLayers = m_layoutBox.view()->frameView() && m_layoutBox.view()->frameView()->paintBehavior() & PaintBehaviorFlattenCompositingLayers;
@@ skipping 507 matching lines @@
                 else
                     clippedEdges |= GraphicsContext::BottomEdge;
             }
             // TODO: support non-integer shadows - crbug.com/334828
             context->drawInnerShadow(border, shadowColor, flooredIntSize(shadowOffset), shadowBlur, shadowSpread, clippedEdges);
         }
     }
 }
 
 } // namespace blink