Use counters for opacity with transform-style:preserve-3d

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index 36fd72053d6480b4c617dda7d2daa6e6123096b6..05a849ab41accbdea4589932c1eec4610074a0ef 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -400,6 +400,7 @@ bool CompositedLayerMapping::updateGraphicsLayerConfiguration()
 
     PaintLayerCompositor* compositor = this->compositor();
     LayoutObject* layoutObject = this->layoutObject();
+    const ComputedStyle& style = layoutObject->styleRef();
 
     bool layerConfigChanged = false;
     setBackgroundLayerPaintsFixedRootBackground(compositor->needsFixedRootBackgroundLayer(&m_owningLayer));
@@ -438,10 +439,7 @@ bool CompositedLayerMapping::updateGraphicsLayerConfiguration()
     if (updateOverflowControlsLayers(requiresHorizontalScrollbarLayer(), requiresVerticalScrollbarLayer(), requiresScrollCornerLayer(), needsAncestorClip))
         layerConfigChanged = true;
 
-    bool hasPerspective = false;
-    // FIXME: Can |style| be really null that late in the DocumentCycle?
-    if (const ComputedStyle* style = layoutObject->style())
-        hasPerspective = style->hasPerspective();
+    bool hasPerspective = style.hasPerspective();
     bool needsChildTransformLayer = hasPerspective && layoutObject->isBox();
     if (updateChildTransformLayer(needsChildTransformLayer))
         layerConfigChanged = true;
@@ -471,8 +469,8 @@ bool CompositedLayerMapping::updateGraphicsLayerConfiguration()
     bool hasChildClippingLayer = compositor->clipsCompositingDescendants(&m_owningLayer) && (hasClippingLayer() || hasScrollingLayer());
     // If we have a border radius or clip path on a scrolling layer, we need a clipping mask to properly
     // clip the scrolled contents, even if there are no composited descendants.
-    bool hasClipPath = layoutObject->style()->clipPath();
-    bool needsChildClippingMask = (hasClipPath || layoutObject->style()->hasBorderRadius()) && (hasChildClippingLayer || isAcceleratedContents(layoutObject) || hasScrollingLayer());
+    bool hasClipPath = style.clipPath();
+    bool needsChildClippingMask = (hasClipPath || style.hasBorderRadius()) && (hasChildClippingLayer || isAcceleratedContents(layoutObject) || hasScrollingLayer());
 
     GraphicsLayer* layerToApplyChildClippingMask = nullptr;
     bool shouldApplyChildClippingMaskOnContents = false;
@@ -556,6 +554,10 @@ bool CompositedLayerMapping::updateGraphicsLayerConfiguration()
 
     updateElementIdAndCompositorMutableProperties();
 
+    m_owningLayer.update3DTransformedDescendantStatus();
+    if (style.preserves3D() && style.hasOpacity() && m_owningLayer.has3DTransformedDescendant())
+        UseCounter::count(layoutObject->document(), UseCounter::OpacityWithPreserve3DQuirk);
+
     return layerConfigChanged;
 }