Index: third_party/WebKit/Source/core/page/scrolling/RootScrollerUtil.cpp |
diff --git a/third_party/WebKit/Source/core/page/scrolling/RootScrollerUtil.cpp b/third_party/WebKit/Source/core/page/scrolling/RootScrollerUtil.cpp |
new file mode 100644 |
index 0000000000000000000000000000000000000000..e7bdf2dd346cc4876f2c59ec4bce9e226881c52c |
--- /dev/null |
+++ b/third_party/WebKit/Source/core/page/scrolling/RootScrollerUtil.cpp |
@@ -0,0 +1,38 @@ |
+// Copyright 2016 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "core/page/scrolling/RootScrollerUtil.h" |
+ |
+#include "core/dom/Document.h" |
+#include "core/dom/Element.h" |
+#include "core/frame/FrameView.h" |
+#include "core/layout/LayoutBox.h" |
+#include "core/layout/LayoutObject.h" |
+#include "core/paint/PaintLayerScrollableArea.h" |
+ |
+namespace blink { |
+ |
+namespace RootScrollerUtil { |
+ |
+ScrollableArea* scrollableAreaFor(const Element& element) |
+{ |
+ if (!element.layoutObject() || !element.layoutObject()->isBox()) |
+ return nullptr; |
+ |
+ LayoutBox* box = toLayoutBox(element.layoutObject()); |
+ |
+ // For a FrameView, we use the layoutViewport rather than the |
+ // getScrollableArea() since that could be the RootFrameViewport. The |
+ // rootScroller's ScrollableArea will be swapped in as the layout viewport |
+ // in RootFrameViewport so we need to ensure we get the layout viewport. |
+ if (box->isDocumentElement()) |
+ return element.document().view()->layoutViewportScrollableArea(); |
+ |
+ return static_cast<PaintInvalidationCapableScrollableArea*>( |
+ box->getScrollableArea()); |
+} |
+ |
+} // namespace RootScrollerUtil |
+ |
+} // namespace blink |