Enable fast/images with slimming paint

Source/core/paint/TransparencyDisplayItem.cpp

Index: Source/core/paint/TransparencyDisplayItem.cpp
diff --git a/Source/core/paint/TransparencyDisplayItem.cpp b/Source/core/paint/TransparencyDisplayItem.cpp
index 77605749f74b035fee3a09e5c0dd1def7c8bb693..d7c7959b79c25d4ca828de5574eea1eed06d0ad9 100644
--- a/Source/core/paint/TransparencyDisplayItem.cpp
+++ b/Source/core/paint/TransparencyDisplayItem.cpp
@@ -5,15 +5,15 @@
 #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();
     if (hasBlendMode)
         context->setCompositeOperation(context->compositeOperation(), m_blendMode);
@@ -40,7 +40,6 @@ WTF::String BeginTransparencyDisplayItem::asDebugString() const
 void EndTransparencyDisplayItem::replay(GraphicsContext* context)
 {
     context->endLayer();
-    context->restore();
 }
 
 #ifndef NDEBUG
@@ -51,4 +50,25 @@ WTF::String EndTransparencyDisplayItem::asDebugString() const
 }
 #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