Make RenderObject::style() return a const object

Source/core/paint/ImagePainter.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/ImagePainter.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/editing/FrameSelection.h"
@@ skipping 36 matching lines @@
     if (areaElement.imageElement() != m_renderImage.node())
         return;
 
     // Even if the theme handles focus ring drawing for entire elements, it won't do it for
     // an area within an image, so we don't call LayoutTheme::supportsFocusRing here.
 
     Path path = areaElement.computePath(&m_renderImage);
     if (path.isEmpty())
         return;
 
-    RenderStyle* areaElementStyle = areaElement.computedStyle();
+    const RenderStyle* areaElementStyle = areaElement.computedStyle();
     unsigned short outlineWidth = areaElementStyle->outlineWidth();
     if (!outlineWidth)
         return;
 
     IntRect focusRect = m_renderImage.absoluteContentBox();
 
     RenderDrawingRecorder drawingRecorder(paintInfo.context, m_renderImage, paintInfo.phase, focusRect);
     if (drawingRecorder.canUseCachedDrawing())
         return;
 
@@ skipping 70 matching lines @@
 
     InterpolationQuality previousInterpolationQuality = context->imageInterpolationQuality();
     context->setImageInterpolationQuality(interpolationQuality);
     context->drawImage(image.get(), alignedRect, SkXfermode::kSrcOver_Mode, m_renderImage.shouldRespectImageOrientation());
     context->setImageInterpolationQuality(previousInterpolationQuality);
 
     InspectorInstrumentation::didPaintImage(&m_renderImage);
 }
 
 } // namespace blink