Remove viewportConstrained plumbing.

sky/engine/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 12 matching lines @@
 }
 
 void CompositingReasonFinder::updateTriggers()
 {
     m_compositingTriggers = 0;
 
     Settings& settings = m_renderView.document().page()->settings();
     if (settings.preferCompositingToLCDTextEnabled()) {
         m_compositingTriggers |= ScrollableInnerFrameTrigger;
         m_compositingTriggers |= OverflowScrollTrigger;
-        m_compositingTriggers |= ViewportConstrainedPositionedTrigger;
     }
 }
 
 bool CompositingReasonFinder::hasOverflowScrollTrigger() const
 {
     return m_compositingTriggers & OverflowScrollTrigger;
 }
 
 CompositingReasons CompositingReasonFinder::directReasons(const RenderLayer* layer) const
 {
@@ skipping 77 matching lines @@
 
         if (const RenderLayer* scrollingAncestor = layer->ancestorScrollingLayer()) {
             if (scrollingAncestor->needsCompositedScrolling() && layer->scrollParent())
                 directReasons |= CompositingReasonOverflowScrollingParent;
         }
 
         if (layer->needsCompositedScrolling())
             directReasons |= CompositingReasonOverflowScrollingTouch;
     }
 
-    if (requiresCompositingForPositionFixed(layer))
-        directReasons |= CompositingReasonPositionFixed;
-
     directReasons |= renderer->additionalCompositingReasons();
 
     ASSERT(!(directReasons & CompositingReasonComboAllStyleDeterminedReasons));
     return directReasons;
 }
 
 bool CompositingReasonFinder::requiresCompositingForAnimation(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();
 }
-
-}