Merge 110563

Source/WebCore/rendering/svg/SVGImageBufferTools.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 103 matching lines @@
     AffineTransform& contentTransformation = currentContentTransformation();
     AffineTransform savedContentTransformation = contentTransformation;
     contentTransformation = subtreeContentTransformation * contentTransformation;
 
     ASSERT(!item->needsLayout());
     item->paint(info, IntPoint());
 
     contentTransformation = savedContentTransformation;
 }
 
-void SVGImageBufferTools::clipToImageBuffer(GraphicsContext* context, const AffineTransform& absoluteTransform, const FloatRect& targetRect, OwnPtr<ImageBuffer>& imageBuffer)
+void SVGImageBufferTools::clipToImageBuffer(GraphicsContext* context, const AffineTransform& absoluteTransform, const FloatRect& targetRect, OwnPtr<ImageBuffer>& imageBuffer, bool safeToClear)
 {
     ASSERT(context);
     ASSERT(imageBuffer);
 
     FloatRect absoluteTargetRect = calculateImageBufferRect(targetRect, absoluteTransform);
 
     // The mask image has been created in the absolute coordinate space, as the image should not be scaled.
     // So the actual masking process has to be done in the absolute coordinate space as well.
     context->concatCTM(absoluteTransform.inverse());
     context->clipToImageBuffer(imageBuffer.get(), absoluteTargetRect);
     context->concatCTM(absoluteTransform);
 
     // When nesting resources, with objectBoundingBox as content unit types, there's no use in caching the
     // resulting image buffer as the parent resource already caches the result.
-    if (!currentContentTransformation().isIdentity())
+    if (safeToClear && !currentContentTransformation().isIdentity())
         imageBuffer.clear();
 }
 
 FloatRect SVGImageBufferTools::clampedAbsoluteTargetRect(const FloatRect& absoluteTargetRect)
 {
     const FloatSize maxImageBufferSize(kMaxImageBufferSize, kMaxImageBufferSize);
     return FloatRect(absoluteTargetRect.location(), absoluteTargetRect.size().shrunkTo(maxImageBufferSize));
 }
 
 IntSize SVGImageBufferTools::clampedAbsoluteSize(const IntSize& absoluteSize)
 {
     const IntSize maxImageBufferSize(kMaxImageBufferSize, kMaxImageBufferSize);
     return absoluteSize.shrunkTo(maxImageBufferSize);
 }
 
 void SVGImageBufferTools::clear2DRotation(AffineTransform& transform)
 {
     AffineTransform::DecomposedType decomposition;
     transform.decompose(decomposition);
     decomposition.angle = 0;
     transform.recompose(decomposition);
 }
 
 }
 
 #endif // ENABLE(SVG)