[WIP] Adding support for <iframe>s to slimming paint.

Source/core/paint/ViewDisplayList.cpp

 // Copyright 2014 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 "config.h"
 #include "core/paint/ViewDisplayList.h"
 
+#include "core/frame/LocalFrame.h"
+#include "core/rendering/RenderLayer.h"
+#include "core/rendering/RenderView.h"
 #include "platform/NotImplemented.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 #ifndef NDEBUG
 #include "core/rendering/RenderObject.h"
 #include "wtf/text/WTFString.h"
 #endif
 
 namespace blink {
 
@@ skipping 30 matching lines @@
 // Update the existing paintList by removing invalidated entries, updating repainted existing ones, and
 // appending new items.
 //
 // The algorithm should be O(|existing paint list| + |newly painted list|). By using the ordering
 // implied by the existing paint list, extra treewalks are avoided.
 void ViewDisplayList::updatePaintList()
 {
     notImplemented();
 }
 
+ViewDisplayList& ViewDisplayList::fromRenderObject(const RenderObject* renderer)
+{
+    ASSERT(renderer);
+
+    RenderView* renderView = renderer->view();
+    ASSERT(renderView);
+
+    FrameView* frameView = renderView->frameView();
+    ASSERT(frameView);
+
+    LocalFrame* localRoot = frameView->frame().localRoot();
+    ASSERT(localRoot);
+
+    FrameView* localRootView = localRoot->view();
+    ASSERT(localRootView);
+
+    return localRootView->viewDisplayList();
+}
+
+ViewDisplayList& ViewDisplayList::fromRenderLayer(const RenderLayer* layer)
+{
+    ASSERT(layer);
+    return fromRenderObject(layer->renderer());
+}
+
 #ifndef NDEBUG
 WTF::String DisplayItem::typeAsDebugString(DisplayItem::Type type)
 {
     switch (type) {
     case DisplayItem::DrawingPaintPhaseBlockBackground: return "DrawingPaintPhaseBlockBackground";
     case DisplayItem::DrawingPaintPhaseChildBlockBackground: return "DrawingPaintPhaseChildBlockBackground";
     case DisplayItem::DrawingPaintPhaseChildBlockBackgrounds: return "DrawingPaintPhaseChildBlockBackgrounds";
     case DisplayItem::DrawingPaintPhaseFloat: return "DrawingPaintPhaseFloat";
     case DisplayItem::DrawingPaintPhaseForeground: return "DrawingPaintPhaseForeground";
     case DisplayItem::DrawingPaintPhaseOutline: return "DrawingPaintPhaseOutline";
@@ skipping 50 matching lines @@
 }
 
 void ViewDisplayList::showDebugData() const
 {
     fprintf(stderr, "paint list: [%s]\n", paintListAsDebugString(m_paintList).utf8().data());
     fprintf(stderr, "new paints: [%s]\n", paintListAsDebugString(m_newPaints).utf8().data());
 }
 #endif
 
 } // namespace blink