Refactor to simplify how layerType is stored on PaintLayers.

third_party/WebKit/Source/core/paint/PaintLayer.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index 11dc3c44a8cbb4f30a2dccb3b745f375ba224e6d..5669d8f3f7ec4f084e23737da887b344260c1975 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -136,8 +136,7 @@ PaintLayerRareData::~PaintLayerRareData()
 }
 
 PaintLayer::PaintLayer(LayoutBoxModelObject* layoutObject, PaintLayerType type)

[pdr., 2016/05/26 00:11:19]

With this gone, can you remove the PaintLayerType argument too? It's plumbed
through a couple calls.

[chrishtr, 2016/05/26 00:37:05]

Done.

-    : m_layerType(type)
-    , m_hasSelfPaintingLayerDescendant(false)
+    : m_hasSelfPaintingLayerDescendant(false)
     , m_hasSelfPaintingLayerDescendantDirty(false)
     , m_isRootLayer(layoutObject->isLayoutView())
     , m_visibleContentStatusDirty(true)
@@ -2453,7 +2452,7 @@ bool PaintLayer::shouldBeSelfPaintingLayer() const
 {
     if (layoutObject()->isLayoutPart() && toLayoutPart(layoutObject())->requiresAcceleratedCompositing())
         return true;
-    return m_layerType == NormalPaintLayer
+    return layoutObject()->layerTypeRequired() == NormalPaintLayer
         || (m_scrollableArea && m_scrollableArea->hasOverlayScrollbars())
         || needsCompositedScrolling();
 }