Set up scroll and clip parents

Source/core/testing/Internals.cpp

Index: Source/core/testing/Internals.cpp
diff --git a/Source/core/testing/Internals.cpp b/Source/core/testing/Internals.cpp
index ad961fa8d953f8c7873be042652f90b0bd0faed0..388eb19f856cb48a05ba35a1600a0d121e967f1e 100644
--- a/Source/core/testing/Internals.cpp
+++ b/Source/core/testing/Internals.cpp
@@ -1773,28 +1773,77 @@ String Internals::elementLayerTreeAsText(Element* element, unsigned flags, Excep
     return layer->backing()->graphicsLayer()->layerTreeAsText(flags);
 }
 
-void Internals::setNeedsCompositedScrolling(Element* element, unsigned needsCompositedScrolling, ExceptionState& es)
+static RenderLayer* getRenderLayerForElement(Element* element, ExceptionState& es)
 {
     if (!element) {
         es.throwDOMException(InvalidAccessError);
-        return;
+        return 0;
     }
 
-    element->document().updateLayout();
-
     RenderObject* renderer = element->renderer();
     if (!renderer || !renderer->isBox()) {
         es.throwDOMException(InvalidAccessError);
-        return;
+        return 0;
     }
 
     RenderLayer* layer = toRenderBox(renderer)->layer();
     if (!layer) {
         es.throwDOMException(InvalidAccessError);
+        return 0;
+    }
+
+    return layer;
+}
+
+void Internals::setNeedsCompositedScrolling(Element* element, unsigned needsCompositedScrolling, ExceptionState& es)
+{
+    if (!element) {
+        es.throwDOMException(InvalidAccessError);
         return;
     }
 
-    layer->setForceNeedsCompositedScrolling(static_cast<RenderLayer::ForceNeedsCompositedScrollingMode>(needsCompositedScrolling));
+    element->document().updateLayout();
+
+    if (RenderLayer* layer = getRenderLayerForElement(element, es))
+        layer->setForceNeedsCompositedScrolling(static_cast<RenderLayer::ForceNeedsCompositedScrollingMode>(needsCompositedScrolling));
+}
+
+bool Internals::isScrollParent(Element* child, Element* parent, ExceptionState& es)
+{
+    RenderLayer* childLayer = getRenderLayerForElement(child, es);
+    RenderLayer* parentLayer = getRenderLayerForElement(parent, es);
+    return childLayer && parentLayer && childLayer->scrollParent() == parentLayer;
+}
+
+bool Internals::isClipParent(Element* child, Element* parent, ExceptionState& es)
+{
+    RenderLayer* childLayer = getRenderLayerForElement(child, es);
+    RenderLayer* parentLayer = getRenderLayerForElement(parent, es);
+    return childLayer && parentLayer && childLayer->clipParent() == parentLayer;
+}
+
+PassRefPtr<ClientRect> Internals::scrollClip(Element* element, ExceptionState& es)
+{
+    RenderLayer* layer = getRenderLayerForElement(element, es);
+    if (!layer || !layer->backing() || !layer->backing()->scrollingLayer())
+        return ClientRect::create();
+
+    return ClientRect::create(
+        FloatRect(
+            layer->backing()->scrollingLayer()->boundsOrigin(),
+            layer->backing()->scrollingLayer()->size()));
+}
+
+PassRefPtr<ClientRect> Internals::ancestorScrollClip(Element* element, ExceptionState& es)
+{
+    RenderLayer* layer = getRenderLayerForElement(element, es);
+    if (!layer || !layer->backing() || !layer->backing()->ancestorScrollClippingLayer())
+        return ClientRect::create();
+
+    return ClientRect::create(
+        FloatRect(
+            layer->backing()->ancestorScrollClippingLayer()->boundsOrigin(),
+            layer->backing()->ancestorScrollClippingLayer()->size()));
 }
 
 String Internals::repaintRectsAsText(Document* document, ExceptionState& es) const