Make RenderObject::style() return a const object

Source/core/rendering/RenderBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 766 matching lines @@
         }
     }
 
     // Similar to how we apply clearance. Go ahead and boost height() to be the place where we're going to position the child.
     setLogicalHeight(logicalHeight() + (result - oldTop));
 
     // Return the final adjusted logical top.
     return result;
 }
 
-static inline LayoutUnit calculateMinimumPageHeight(RenderStyle* renderStyle, RootInlineBox* lastLine, LayoutUnit lineTop, LayoutUnit lineBottom)
+static inline LayoutUnit calculateMinimumPageHeight(const RenderStyle* renderStyle, RootInlineBox* lastLine, LayoutUnit lineTop, LayoutUnit lineBottom)
 {
     // We may require a certain minimum number of lines per page in order to satisfy
     // orphans and widows, and that may affect the minimum page height.
     unsigned lineCount = std::max<unsigned>(renderStyle->hasAutoOrphans() ? 1 : renderStyle->orphans(), renderStyle->widows());
     if (lineCount > 1) {
         RootInlineBox* line = lastLine;
         for (unsigned i = 1; i < lineCount && line->prevRootBox(); i++)
             line = line->prevRootBox();
 
         // FIXME: Paginating using line overflow isn't all fine. See FIXME in
@@ skipping 293 matching lines @@
 // Our MarginInfo state used when laying out block children.
 MarginInfo::MarginInfo(RenderBlockFlow* blockFlow, LayoutUnit beforeBorderPadding, LayoutUnit afterBorderPadding)
     : m_canCollapseMarginAfterWithLastChild(true)
     , m_atBeforeSideOfBlock(true)
     , m_atAfterSideOfBlock(false)
     , m_hasMarginBeforeQuirk(false)
     , m_hasMarginAfterQuirk(false)
     , m_determinedMarginBeforeQuirk(false)
     , m_discardMargin(false)
 {
-    RenderStyle* blockStyle = blockFlow->style();
+    const RenderStyle* blockStyle = blockFlow->style();
     ASSERT(blockFlow->isRenderView() || blockFlow->parent());
     m_canCollapseWithChildren = !blockFlow->createsNewFormattingContext() && !blockFlow->isRenderFlowThread() && !blockFlow->isRenderView();
 
     m_canCollapseMarginBeforeWithChildren = m_canCollapseWithChildren && !beforeBorderPadding && blockStyle->marginBeforeCollapse() != MSEPARATE;
 
     // If any height other than auto is specified in CSS, then we don't collapse our bottom
     // margins with our children's margins. To do otherwise would be to risk odd visual
     // effects when the children overflow out of the parent block and yet still collapse
     // with it. We also don't collapse if we have any bottom border/padding.
     m_canCollapseMarginAfterWithChildren = m_canCollapseWithChildren && !afterBorderPadding
@@ skipping 823 matching lines @@
     return result;
 }
 
 void RenderBlockFlow::createFloatingObjects()
 {
     m_floatingObjects = adoptPtr(new FloatingObjects(this, isHorizontalWritingMode()));
 }
 
 void RenderBlockFlow::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
 {
-    RenderStyle* oldStyle = style();
+    const RenderStyle* oldStyle = style();
     s_canPropagateFloatIntoSibling = oldStyle ? !isFloatingOrOutOfFlowPositioned() && !avoidsFloats() : false;
     if (oldStyle && parent() && diff.needsFullLayout() && oldStyle->position() != newStyle.position()
         && containsFloats() && !isFloating() && !isOutOfFlowPositioned() && newStyle.hasOutOfFlowPosition())
             markAllDescendantsWithFloatsForLayout();
 
     RenderBlock::styleWillChange(diff, newStyle);
 }
 
 void RenderBlockFlow::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
 {
@@ skipping 1194 matching lines @@
     FrameView* frameView = document().view();
     LayoutUnit top = (style()->position() == FixedPosition) ? 0 : frameView->scrollOffset().height();
     int visibleHeight = frameView->visibleContentRect(IncludeScrollbars).height();
     if (size().height() < visibleHeight)
         top += (visibleHeight - size().height()) / 2;
     setY(top);
     dialog->setCentered(top);
 }
 
 } // namespace blink