Make the LayoutRect->FloatRect constructor explicit.

Source/core/layout/svg/LayoutSVGBlock.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * 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.
  *
@@ skipping 81 matching lines @@
     return SVGLayoutSupport::pushMappingToContainer(this, ancestorToStopAt, geometryMap);
 }
 
 LayoutRect LayoutSVGBlock::clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* paintInvalidationState) const
 {
     return SVGLayoutSupport::clippedOverflowRectForPaintInvalidation(*this, paintInvalidationContainer, paintInvalidationState);
 }
 
 void LayoutSVGBlock::mapRectToPaintInvalidationBacking(const LayoutBoxModelObject* paintInvalidationContainer, LayoutRect& rect, const PaintInvalidationState* paintInvalidationState) const
 {
-    FloatRect paintInvalidationRect = rect;
+    FloatRect paintInvalidationRect(rect);
     const LayoutSVGRoot& svgRoot = SVGLayoutSupport::mapRectToSVGRootForPaintInvalidation(*this, paintInvalidationRect, rect);
     svgRoot.mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect, paintInvalidationState);
 }
 
 bool LayoutSVGBlock::nodeAtPoint(HitTestResult&, const HitTestLocation&, const LayoutPoint&, HitTestAction)
 {
     ASSERT_NOT_REACHED();
     return false;
 }
 
 void LayoutSVGBlock::invalidateTreeIfNeeded(PaintInvalidationState& paintInvalidationState)
 {
     if (!shouldCheckForPaintInvalidation(paintInvalidationState))
         return;
 
     ForceHorriblySlowRectMapping slowRectMapping(&paintInvalidationState);
     LayoutBlockFlow::invalidateTreeIfNeeded(paintInvalidationState);
 }
 
 }