Fix slimming paint clipping and add a debug fill color

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/rendering/RenderObject.h"
 #include "core/rendering/RenderView.h"
 #include "platform/NotImplemented.h"
@@ skipping 19 matching lines @@
     OwnPtr<AtomicPaintChunk> paintChunk = adoptPtr(new AtomicPaintChunk(m_context->endRecording(), m_renderer, m_phase));
     ASSERT(m_renderer->view());
     m_renderer->view()->viewDisplayList().add(paintChunk.release());
 }
 
 const PaintCommandList& ViewDisplayList::paintCommandList()
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
 
     updatePaintCommandList();
-    return m_paintList;
+    return m_newPaints;
 }
 
 void ViewDisplayList::add(WTF::PassOwnPtr<AtomicPaintChunk> atomicPaintChunk)
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
     m_newPaints.append(atomicPaintChunk);
 }
 
 void ViewDisplayList::invalidate(const RenderObject* renderer)
 {
@@ skipping 11 matching lines @@
 // 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::updatePaintCommandList()
 {
     notImplemented();
 }
 
 } // namespace blink