NOT FOR REVIEW - Update comp-scrolling state at a well defined point in the pipeline.

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 ee84fbfc31be8ffef88fe548329f7aeb731d54f6..727b878afd60555082b1ebcccedf24162456f900 100644
--- a/Source/core/testing/Internals.cpp
+++ b/Source/core/testing/Internals.cpp
@@ -1570,6 +1570,26 @@ String Internals::layerTreeAsText(Document* document, ExceptionCode& ec) const
     return layerTreeAsText(document, 0, ec);
 }
 
+String Internals::layerTreeAsText(Document* document, unsigned flags, ExceptionCode& ec) const
+{
+    if (!document || !document->frame()) {
+        ec = INVALID_ACCESS_ERR;
+        return String();
+    }
+
+    LayerTreeFlags layerTreeFlags = 0;
+    if (flags & LAYER_TREE_INCLUDES_VISIBLE_RECTS)
+        layerTreeFlags |= LayerTreeFlagsIncludeVisibleRects;
+    if (flags & LAYER_TREE_INCLUDES_TILE_CACHES)
+        layerTreeFlags |= LayerTreeFlagsIncludeTileCaches;
+    if (flags & LAYER_TREE_INCLUDES_REPAINT_RECTS)
+        layerTreeFlags |= LayerTreeFlagsIncludeRepaintRects;
+    if (flags & LAYER_TREE_INCLUDES_PAINTING_PHASES)
+        layerTreeFlags |= LayerTreeFlagsIncludePaintingPhases;
+
+    return document->frame()->layerTreeAsText(layerTreeFlags);
+}
+
 static PassRefPtr<NodeList> paintOrderList(Element* element, ExceptionCode& ec, RenderLayer::PaintOrderListType type)
 {
     if (!element) {
@@ -1606,24 +1626,28 @@ PassRefPtr<NodeList> Internals::paintOrderListAfterPromote(Element* element, Exc
     return paintOrderList(element, ec, RenderLayer::AfterPromote);
 }
 
-String Internals::layerTreeAsText(Document* document, unsigned flags, ExceptionCode& ec) const
+void Internals::setNeedsCompositedScrolling(Element* element, unsigned needsCompositedScrolling, ExceptionCode& ec)
 {
-    if (!document || !document->frame()) {
+    if (!element) {
         ec = INVALID_ACCESS_ERR;
-        return String();
+        return;
     }
 
-    LayerTreeFlags layerTreeFlags = 0;
-    if (flags & LAYER_TREE_INCLUDES_VISIBLE_RECTS)
-        layerTreeFlags |= LayerTreeFlagsIncludeVisibleRects;
-    if (flags & LAYER_TREE_INCLUDES_TILE_CACHES)
-        layerTreeFlags |= LayerTreeFlagsIncludeTileCaches;
-    if (flags & LAYER_TREE_INCLUDES_REPAINT_RECTS)
-        layerTreeFlags |= LayerTreeFlagsIncludeRepaintRects;
-    if (flags & LAYER_TREE_INCLUDES_PAINTING_PHASES)
-        layerTreeFlags |= LayerTreeFlagsIncludePaintingPhases;
+    element->document()->updateLayout();
 
-    return document->frame()->layerTreeAsText(layerTreeFlags);
+    RenderObject* renderer = element->renderer();
+    if (!renderer || !renderer->isBox()) {
+        ec = INVALID_ACCESS_ERR;
+        return;
+    }
+
+    RenderLayer* layer = toRenderBox(renderer)->layer();
+    if (!layer) {
+        ec = INVALID_ACCESS_ERR;
+        return;
+    }
+
+    layer->setForceNeedsCompositedScrolling(static_cast<RenderLayer::ForceNeedsCompositedScrollingMode>(needsCompositedScrolling));
 }
 
 String Internals::repaintRectsAsText(Document* document, ExceptionCode& ec) const