Make RenderObject::style() return a const object

Source/core/paint/ObjectPainter.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/ObjectPainter.h"
 
 #include "core/layout/LayoutTheme.h"
 #include "core/paint/RenderDrawingRecorder.h"
 #include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderObject.h"
 #include "core/rendering/style/RenderStyle.h"
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
 
 namespace blink {
 
-void ObjectPainter::paintFocusRing(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, RenderStyle* style)
+void ObjectPainter::paintFocusRing(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, const RenderStyle* style)
 {
     Vector<LayoutRect> focusRingRects;
     m_renderObject.addFocusRingRects(focusRingRects, paintOffset);
     ASSERT(style->outlineStyleIsAuto());
     Vector<IntRect> focusRingIntRects;
     for (size_t i = 0; i < focusRingRects.size(); ++i)
         focusRingIntRects.append(pixelSnappedIntRect(focusRingRects[i]));
     paintInfo.context->drawFocusRing(focusRingIntRects, style->outlineWidth(), style->outlineOffset(), m_renderObject.resolveColor(style, CSSPropertyOutlineColor));
 }
 
 void ObjectPainter::paintOutline(const PaintInfo& paintInfo, const LayoutRect& paintRect)
 {
-    RenderStyle* styleToUse = m_renderObject.style();
+    const RenderStyle* styleToUse = m_renderObject.style();
     if (!styleToUse->hasOutline())
         return;
 
     RenderDrawingRecorder recorder(paintInfo.context, m_renderObject, paintInfo.phase, paintRect);
     if (recorder.canUseCachedDrawing())
         return;
 
     if (styleToUse->outlineStyleIsAuto()) {
         if (LayoutTheme::theme().shouldDrawDefaultFocusRing(&m_renderObject)) {
             // Only paint the focus ring by hand if the theme isn't able to draw the focus ring.
@@ skipping 299 matching lines @@
         quad[1] = FloatPoint(x1, y2 - std::max(adjacentWidth2, 0));
         quad[2] = FloatPoint(x2, y2 - std::max(-adjacentWidth2, 0));
         quad[3] = FloatPoint(x2, y1 + std::max(-adjacentWidth1, 0));
         break;
     }
 
     graphicsContext->fillPolygon(4, quad, color, antialias);
 }
 
 } // namespace blink