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

Source/core/paint/DrawingRecorder.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/DrawingRecorder.h"
 
 #include "core/rendering/RenderObject.h"
 #include "core/rendering/RenderView.h"
 #include "platform/RuntimeEnabledFeatures.h"
@@ skipping 35 matching lines @@
 #if ENABLE(ASSERT)
     s_inDrawingRecorder = false;
 #endif
 
     RefPtr<DisplayList> displayList = m_context->endRecording();
     if (!displayList->picture()->approximateOpCount())
         return;
     ASSERT(displayList->bounds() == m_bounds);
     OwnPtr<DrawingDisplayItem> drawingItem = adoptPtr(
         new DrawingDisplayItem(displayList->picture(), m_bounds.location(), m_phase, m_renderer));
-    ASSERT(m_renderer->view());
-    m_renderer->view()->viewDisplayList().add(drawingItem.release());
+
+    ViewDisplayList::fromRenderObject(m_renderer).add(drawingItem.release());

[chrishtr, 2014/11/01 23:44:10]

I hadn't mentioned it yet, but since your CL forces the issue, we should put the
DisplayItemList (and rename it to that instead of ViewDisplayList) on
paintInvalidationContainer->layer()->graphicsLayerBacking(). If we do that then
the rest we get for free, e.g. traversing across non-composited vs composited
iframes, or eventually turning off compositing below the root document entirely.


GraphicsLayer will also be the right entry point for sending the DisplayList to
cc as we implement the rest of Slimming Paint, and allow us to easily get to the
phase 1 launch point of painting existing cc::Layers w/Slimming Paint.

[trchen, 2014/11/02 10:36:46]

Ah ha, that makes sense. I will revise as you planned.

 }
 
 #ifndef NDEBUG
 WTF::String DrawingDisplayItem::asDebugString() const
 {
     return String::format("{%s, type: \"%s\", location: [%f,%f]}",
         rendererDebugString(renderer()).utf8().data(), typeAsDebugString(type()).utf8().data(),
         m_location.x(), m_location.y());
 }
 #endif
 
 } // namespace blink