Add protobuf serialization to DisplayItemList

cc/playback/transform_display_item.cc

Index: cc/playback/transform_display_item.cc
diff --git a/cc/playback/transform_display_item.cc b/cc/playback/transform_display_item.cc
index df7ca1b8e563944ec3cdf8e4ebd35f5afe329e39..d0e7de79499c947f83661ad87370ea120d228d36 100644
--- a/cc/playback/transform_display_item.cc
+++ b/cc/playback/transform_display_item.cc
@@ -6,6 +6,8 @@
 
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "cc/proto/display_item.pb.h"
+#include "cc/proto/gfx_conversions.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace cc {
@@ -24,6 +26,22 @@ void TransformDisplayItem::SetNew(const gfx::Transform& transform) {
                       0 /* external_memory_usage */);
 }
 
+void TransformDisplayItem::ToProtobuf(proto::DisplayItem* proto) const {
+  proto->set_type(proto::DisplayItem::Type_Transform);
+
+  proto::TransformDisplayItem* details = proto->mutable_transform_item();
+  TransformToProto(transform_, details->mutable_transform());
+}
+
+void TransformDisplayItem::FromProtobuf(const proto::DisplayItem& proto) {
+  DCHECK_EQ(proto::DisplayItem::Type_Transform, proto.type());
+
+  const proto::TransformDisplayItem& details = proto.transform_item();
+  gfx::Transform transform = ProtoToTransform(details.transform());
+
+  SetNew(transform);
+}
+
 void TransformDisplayItem::Raster(SkCanvas* canvas,
                                   const gfx::Rect& canvas_target_playback_rect,
                                   SkPicture::AbortCallback* callback) const {
@@ -46,6 +64,14 @@ EndTransformDisplayItem::EndTransformDisplayItem() {
 EndTransformDisplayItem::~EndTransformDisplayItem() {
 }
 
+void EndTransformDisplayItem::ToProtobuf(proto::DisplayItem* proto) const {
+  proto->set_type(proto::DisplayItem::Type_EndTransform);
+}
+
+void EndTransformDisplayItem::FromProtobuf(const proto::DisplayItem& proto) {
+  DCHECK_EQ(proto::DisplayItem::Type_EndTransform, proto.type());
+}
+
 void EndTransformDisplayItem::Raster(
     SkCanvas* canvas,
     const gfx::Rect& canvas_target_playback_rect,