Update from https://crrev.com/306655

cc/resources/transparency_display_item.cc

+// 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 "cc/resources/transparency_display_item.h"
+
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "third_party/skia/include/core/SkXfermode.h"
+#include "ui/gfx/skia_util.h"
+
+namespace cc {
+
+TransparencyDisplayItem::TransparencyDisplayItem(float opacity,
+                                                 SkXfermode::Mode blend_mode)
+    : opacity_(opacity), blend_mode_(blend_mode) {
+}
+
+TransparencyDisplayItem::~TransparencyDisplayItem() {
+}
+
+void TransparencyDisplayItem::Raster(SkCanvas* canvas,
+                                     SkDrawPictureCallback* callback) const {
+  SkPaint paint;
+  paint.setXfermodeMode(blend_mode_);
+  paint.setAlpha(opacity_ * 255);
+  canvas->saveLayer(NULL, &paint);
+}
+
+bool TransparencyDisplayItem::IsSuitableForGpuRasterization() const {
+  return true;
+}
+
+int TransparencyDisplayItem::ApproximateOpCount() const {
+  return 1;
+}
+
+size_t TransparencyDisplayItem::PictureMemoryUsage() const {
+  return sizeof(float) + sizeof(SkXfermode::Mode);
+}
+
+EndTransparencyDisplayItem::EndTransparencyDisplayItem() {
+}
+
+EndTransparencyDisplayItem::~EndTransparencyDisplayItem() {
+}
+
+void EndTransparencyDisplayItem::Raster(SkCanvas* canvas,
+                                        SkDrawPictureCallback* callback) const {
+  canvas->restore();
+}
+
+bool EndTransparencyDisplayItem::IsSuitableForGpuRasterization() const {
+  return true;
+}
+
+int EndTransparencyDisplayItem::ApproximateOpCount() const {
+  return 0;
+}
+
+size_t EndTransparencyDisplayItem::PictureMemoryUsage() const {
+  return 0;
+}
+
+}  // namespace cc