Make RenderObject::style() return a const object

Source/core/rendering/compositing/CompositingReasonFinder.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/rendering/compositing/CompositingReasonFinder.h"
 
 #include "core/CSSPropertyNames.h"
 #include "core/dom/Document.h"
 #include "core/frame/FrameView.h"
@@ skipping 63 matching lines @@
     return m_renderView.frameView()->isScrollable();
 }
 
 CompositingReasons CompositingReasonFinder::potentialCompositingReasonsFromStyle(RenderObject* renderer) const
 {
     if (RuntimeEnabledFeatures::slimmingPaintCompositorLayerizationEnabled())
         return CompositingReasonNone;
 
     CompositingReasons reasons = CompositingReasonNone;
 
-    RenderStyle* style = renderer->style();
+    const RenderStyle* style = renderer->style();
 
     if (requiresCompositingForTransform(renderer))
         reasons |= CompositingReason3DTransform;
 
     if (style->backfaceVisibility() == BackfaceVisibilityHidden)
         reasons |= CompositingReasonBackfaceVisibilityHidden;
 
     if (requiresCompositingForAnimation(style))
         reasons |= CompositingReasonActiveAnimation;
 
@@ skipping 68 matching lines @@
 
     if (requiresCompositingForPositionFixed(layer))
         directReasons |= CompositingReasonPositionFixed;
 
     directReasons |= renderer->additionalCompositingReasons();
 
     ASSERT(!(directReasons & CompositingReasonComboAllStyleDeterminedReasons));
     return directReasons;
 }
 
-bool CompositingReasonFinder::requiresCompositingForAnimation(RenderStyle* style) const
+bool CompositingReasonFinder::requiresCompositingForAnimation(const RenderStyle* style) const
 {
     if (style->subtreeWillChangeContents())
         return style->isRunningAnimationOnCompositor();
 
     return style->shouldCompositeForCurrentAnimations();
 }
 
 bool CompositingReasonFinder::requiresCompositingForPositionFixed(const RenderLayer* layer) const
 {
     if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger))
         return false;
     // Don't promote fixed position elements that are descendants of a non-view container, e.g. transformed elements.
     // They will stay fixed wrt the container rather than the enclosing frame.
     return layer->scrollsWithViewport() && m_renderView.frameView()->isScrollable();
 }
 
 bool CompositingReasonFinder::requiresCompositingForScrollBlocksOn(const RenderObject* renderer) const
 {
     // Note that the other requires* functions run at RenderObject::styleDidChange time and so can rely
     // only on the style of their object.  This function runs at CompositingRequirementsUpdater::update
     // time, and so can consider the style of other objects.
-    RenderStyle* style = renderer->style();
+    const RenderStyle* style = renderer->style();
 
     // We should only get here by CompositingReasonScrollBlocksOn being a potential compositing reason.
     ASSERT(style->hasScrollBlocksOn() && !renderer->isDocumentElement());
 
     // scroll-blocks-on style is propagated from the document element to the document.
     ASSERT(!renderer->isRenderView()
         || !renderer->document().documentElement()
         || !renderer->document().documentElement()->renderer()
         || renderer->document().documentElement()->renderer()->style()->scrollBlocksOn() == style->scrollBlocksOn());
 
@@ skipping 18 matching lines @@
             // Either way, we don't need to require compositing for scroll blocks on.  This avoids
             // enabling compositing by default, and avoids cluttering the root layers compositing reasons.
             return false;
         }
     }
 
     return true;
 }
 
 }