Enable fast/images with slimming paint

Source/core/paint/TransparencyDisplayItem.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/TransparencyDisplayItem.h"
 
+#include "core/rendering/RenderObject.h"
+#include "core/rendering/RenderView.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsContext.h"
 
 namespace blink {
 
 void BeginTransparencyDisplayItem::replay(GraphicsContext* context)
 {
     context->save();
     context->clip(m_clipRect);
 
     bool hasBlendMode = this->hasBlendMode();
@@ skipping 26 matching lines @@
 }
 
 #ifndef NDEBUG
 WTF::String EndTransparencyDisplayItem::asDebugString() const
 {
     return String::format("{%s, type: \"%s\"}",
         rendererDebugString(renderer()).utf8().data(), typeAsDebugString(type()).utf8().data());
 }
 #endif
 
+TransparencyRecorder::TransparencyRecorder(GraphicsContext* graphicsContext, const RenderObject* renderer, DisplayItem::Type type, const LayoutRect& clipRect, const WebBlendMode& blendMode, const float opacity)
+    : m_renderer(renderer)
+    , m_type(type)
+    , m_graphicsContext(graphicsContext)
+{
+    OwnPtr<BeginTransparencyDisplayItem> beginTransparencyDisplayItem = adoptPtr(new BeginTransparencyDisplayItem(renderer, type, clipRect, blendMode, opacity));
+    if (RuntimeEnabledFeatures::slimmingPaintEnabled())
+        renderer->view()->viewDisplayList().add(beginTransparencyDisplayItem.release());
+    else
+        beginTransparencyDisplayItem->replay(graphicsContext);
+}
+
+TransparencyRecorder::~TransparencyRecorder()
+{
+    OwnPtr<EndTransparencyDisplayItem> endTransparencyDisplayItem = adoptPtr(new EndTransparencyDisplayItem(m_renderer, m_type));
+    if (RuntimeEnabledFeatures::slimmingPaintEnabled())
+        m_renderer->view()->viewDisplayList().add(endTransparencyDisplayItem.release());
+    else
+        endTransparencyDisplayItem->replay(m_graphicsContext);
+}
+
 } // namespace blink