tracing: Make ConvertableToTraceFormat move-only scoped_ptr

cc/playback/display_item_list.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/playback/display_item_list.h"
 
 #include <stddef.h>
 
 #include <string>
 
@@ skipping 219 matching lines @@
   // TODO(jbroman): Does anything else owned by this class substantially
   // contribute to memory usage?
 
   return memory_usage;
 }
 
 bool DisplayItemList::ShouldBeAnalyzedForSolidColor() const {
   return ApproximateOpCount() <= kOpCountThatIsOkToAnalyze;
 }
 
-scoped_refptr<base::trace_event::ConvertableToTraceFormat>
+scoped_ptr<base::trace_event::ConvertableToTraceFormat>
 DisplayItemList::AsValue(bool include_items) const {
-  scoped_refptr<base::trace_event::TracedValue> state =
-      new base::trace_event::TracedValue();
+  scoped_ptr<base::trace_event::TracedValue> state(
+      new base::trace_event::TracedValue());
 
   state->BeginDictionary("params");
   if (include_items) {
     state->BeginArray("items");
     size_t item_index = 0;
     for (const DisplayItem& item : items_) {
       item.AsValueInto(item_index < visual_rects_.size()
                            ? visual_rects_[item_index]
                            : gfx::Rect(),
                        state.get());
@@ skipping 12 matching lines @@
     canvas->clipRect(gfx::RectToSkRect(layer_rect_));
     Raster(canvas, NULL, gfx::Rect(), 1.f);
     skia::RefPtr<SkPicture> picture =
         skia::AdoptRef(recorder.endRecordingAsPicture());
 
     std::string b64_picture;
     PictureDebugUtil::SerializeAsBase64(picture.get(), &b64_picture);
     state->SetString("skp64", b64_picture);
   }
 
-  return state;
+  return std::move(state);
 }
 
 void DisplayItemList::EmitTraceSnapshot() const {
   TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
       TRACE_DISABLED_BY_DEFAULT("cc.debug.display_items") ","
       TRACE_DISABLED_BY_DEFAULT("cc.debug.picture") ","
       TRACE_DISABLED_BY_DEFAULT("devtools.timeline.picture"),
       "cc::DisplayItemList", this,
       TracedDisplayItemList::AsTraceableDisplayItemList(this,
           DisplayItemsTracingEnabled()));
@@ skipping 25 matching lines @@
 bool DisplayItemList::HasDiscardableImageInRect(
     const gfx::Rect& layer_rect) const {
   return image_map_.HasDiscardableImageInRect(layer_rect);
 }
 
 bool DisplayItemList::MayHaveDiscardableImages() const {
   return !image_map_.empty();
 }
 
 }  // namespace cc