Never layer-ize RenderInlines.

This removes support for opacity, filters and clip-path
on RenderInlines. If you want inline content that uses
these properties you need to use an inline-block. We
may want to add back support for opacity or filters
on inlines eventually, but we'd implement it differently
and right now they're getting in the way.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/950963003

engine/core/rendering/RenderInline.h

@@ -114,7 +114,7 @@ private:
 
     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset) override final;
 
-    virtual LayerType layerTypeRequired() const override { return createsGroup() || hasClipPath() ? NormalLayer : NoLayer; }
+    virtual LayerType layerTypeRequired() const override { return NoLayer; }
 
     virtual LayoutUnit offsetLeft() const override final;
     virtual LayoutUnit offsetTop() const override final;