Make RenderObject::style() return a const object

Source/core/rendering/TextAutosizer.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 204 matching lines @@
 
     return (linkCount >= 3);
 }
 
 static bool blockHeightConstrained(const RenderBlock* block)
 {
     // FIXME: Propagate constrainedness down the tree, to avoid inefficiently walking back up from each box.
     // FIXME: This code needs to take into account vertical writing modes.
     // FIXME: Consider additional heuristics, such as ignoring fixed heights if the content is already overflowing before autosizing kicks in.
     for (; block; block = block->containingBlock()) {
-        RenderStyle* style = block->style();
+        const RenderStyle* style = block->style();
         if (style->overflowY() >= OSCROLL)
             return false;
         if (style->height().isSpecified() || style->maxHeight().isSpecified() || block->isOutOfFlowPositioned()) {
             // Some sites (e.g. wikipedia) set their html and/or body elements to height:100%,
             // without intending to constrain the height of the content within them.
             return !block->isDocumentElement() && !block->isBody();
         }
         if (block->isFloating())
             return false;
     }
@@ skipping 323 matching lines @@
     ASSERT(page);
     return page->settings().pinchVirtualViewportEnabled() ?
         page->frameHost().pinchViewport().size() :
         page->deprecatedLocalMainFrame()->view()->unscaledVisibleContentSize(IncludeScrollbars);
 }
 
 void TextAutosizer::resetMultipliers()
 {
     RenderObject* renderer = m_document->renderView();
     while (renderer) {
-        if (RenderStyle* style = renderer->style()) {
+        if (const RenderStyle* style = renderer->style()) {
             if (style->textAutosizingMultiplier() != 1)
                 applyMultiplier(renderer, 1, LayoutNeeded);
         }
         renderer = renderer->nextInPreOrder();
     }
 }
 
 void TextAutosizer::setAllTextNeedsLayout()
 {
     RenderObject* renderer = m_document->renderView();
@@ skipping 98 matching lines @@
     Node* node = renderer->generatingNode();
     if (!node || !node->isElementNode())
         return 0;
 
     FingerprintSourceData data;
     if (const RenderObject* parent = parentElementRenderer(renderer))
         data.m_parentHash = getFingerprint(parent);
 
     data.m_qualifiedNameHash = QualifiedNameHash::hash(toElement(node)->tagQName());
 
-    if (RenderStyle* style = renderer->style()) {
+    if (const RenderStyle* style = renderer->style()) {
         data.m_packedStyleProperties = style->direction();
         data.m_packedStyleProperties |= (style->position() << 1);
         data.m_packedStyleProperties |= (style->floating() << 4);
         data.m_packedStyleProperties |= (style->display() << 6);
         data.m_packedStyleProperties |= (style->width().type() << 11);
         // packedStyleProperties effectively using 15 bits now.
 
         // consider for adding: writing mode, padding.
 
         data.m_width = style->width().getFloatValue();
@@ skipping 258 matching lines @@
         child = (firstOrLast == First) ? child->nextSibling() : child->previousSibling();
     }
     --depth;
 
     return 0;
 }
 
 void TextAutosizer::applyMultiplier(RenderObject* renderer, float multiplier, RelayoutBehavior relayoutBehavior)
 {
     ASSERT(renderer && renderer->style());
-    RenderStyle* currentStyle = renderer->style();
+    RenderStyle* currentStyle = renderer->deprecatedMutableStyle();

[rune, 2015/01/29 23:16:32]

You need a mutable style here for storing a RefPtr in
m_stylesRetainedDuringLayout?

[Julien - ping for review, 2015/02/10 07:33:19]

Indeed.

     if (currentStyle->textAutosizingMultiplier() == multiplier)
         return;
 
     // We need to clone the render style to avoid breaking style sharing.
     RefPtr<RenderStyle> style = RenderStyle::clone(currentStyle);
     style->setTextAutosizingMultiplier(multiplier);
     style->setUnique();
 
     switch (relayoutBehavior) {
     case AlreadyInLayout:
@@ skipping 191 matching lines @@
     }
     return computedSize;
 }
 
 void TextAutosizer::trace(Visitor* visitor)
 {
     visitor->trace(m_document);
 }
 
 } // namespace blink