[Slimming Paint] Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/CompositingDisplayItem.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 "platform/graphics/paint/CompositingDisplayItem.h"
 
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsContext.h"
+#include "platform/graphics/paint/DisplayItems.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "public/platform/WebDisplayItemList.h"
 
 namespace blink {
 
 void BeginCompositingDisplayItem::replay(GraphicsContext& context)
 {
     context.beginLayer(m_opacity, m_xferMode, m_hasBounds ? &m_bounds : nullptr, m_colorFilter);
 }
 
 void BeginCompositingDisplayItem::appendToWebDisplayItemList(WebDisplayItemList* list) const
 {
     SkRect bounds = WebCoreFloatRectToSKRect(m_bounds);
     list->appendCompositingItem(m_opacity, m_xferMode, m_hasBounds ? &bounds : nullptr, GraphicsContext::WebCoreColorFilterToSkiaColorFilter(m_colorFilter).get());
 }
 
+void BeginCompositingDisplayItem::appendByMoving(DisplayItems& destination)
+{
+    FloatRect* bounds = m_hasBounds ? &m_bounds : nullptr;
+    destination.emplaceBack<BeginCompositingDisplayItem>(
+        DisplayItemClientWrapperHelper(*this),
+        m_xferMode, m_opacity, bounds, m_colorFilter);
+}
+
 #ifndef NDEBUG
 void BeginCompositingDisplayItem::dumpPropertiesAsDebugString(WTF::StringBuilder& stringBuilder) const
 {
     DisplayItem::dumpPropertiesAsDebugString(stringBuilder);
     stringBuilder.append(WTF::String::format(", xferMode: %d, opacity: %f", m_xferMode, m_opacity));
     if (m_hasBounds)
         stringBuilder.append(WTF::String::format(", bounds: [%f, %f, %f, %f]", m_bounds.location().x(), m_bounds.location().y(), m_bounds.size().width(), m_bounds.size().height()));
 }
 #endif
 
 void EndCompositingDisplayItem::replay(GraphicsContext& context)
 {
     context.endLayer();
 }
 
 void EndCompositingDisplayItem::appendToWebDisplayItemList(WebDisplayItemList* list) const
 {
     list->appendEndCompositingItem();
 }
 
+void EndCompositingDisplayItem::appendByMoving(DisplayItems& destination)
+{
+    destination.emplaceBack<EndCompositingDisplayItem>(
+        DisplayItemClientWrapperHelper(*this));
+}
+
 } // namespace blink