Add protobuf serialization to DisplayItemList

cc/playback/clip_path_display_item.cc

 // Copyright 2015 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/clip_path_display_item.h"
 
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "cc/proto/display_item.pb.h"
+#include "cc/proto/skia_conversions.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace cc {
 
 ClipPathDisplayItem::ClipPathDisplayItem() {
 }
 
 ClipPathDisplayItem::~ClipPathDisplayItem() {
 }
 
 void ClipPathDisplayItem::SetNew(const SkPath& clip_path,
                                  SkRegion::Op clip_op,
                                  bool antialias) {
   clip_path_ = clip_path;
   clip_op_ = clip_op;
   antialias_ = antialias;
 
   // The size of SkPath's external storage is not currently accounted for (and
   // may well be shared anyway).
   DisplayItem::SetNew(true /* suitable_for_gpu_raster */, 1 /* op_count */,
                       0 /* external_memory_usage */);
 }
 
+void ClipPathDisplayItem::ToProtobuf(proto::DisplayItem* proto) {
+  proto->set_type(proto::DisplayItem::Type_ClipPath);
+
+  proto::ClipPathDisplayItem* details = proto->mutable_details_clip_path();
+  details->set_clip_op(SkRegionOpToProto(clip_op_));
+  details->set_antialias(antialias_);
+
+  // Just use skia's serialization method for the SkPath for now.
+  size_t path_size = clip_path_.writeToMemory(nullptr);
+  if (path_size > 0) {
+    scoped_ptr<char[]> buffer(new char[path_size]);
+    clip_path_.writeToMemory(buffer.get());
+    details->set_clip_path(buffer.get(), path_size);

[vmpstr, 2015/10/26 17:46:17]

What's the parameter to set_clip_path? Is this a copy? It's weird to just pass a
raw ptr to a scoped_ptr thing that is deleted immediately.

Can you make it std::string(buffer.get()) to make it explicit?

[David Trainor- moved to gerrit, 2015/10/26 20:42:56]

I believe protobufs always copy the data passed in so they're self-contained
objects.  I can cast it to a string if you'd prefer that though.  It'll just do
the copy to the string constructor then ref the data internally in the protobuf.

+  }
+}
+
+void ClipPathDisplayItem::FromProtobuf(const proto::DisplayItem& proto) {
+  DCHECK_EQ(proto::DisplayItem::Type_ClipPath, proto.type());
+
+  const proto::ClipPathDisplayItem& details = proto.details_clip_path();
+  SkRegion::Op clip_op = SkRegionOpFromProto(details.clip_op());
+  bool antialias = details.antialias();
+
+  SkPath clip_path;
+  if (details.has_clip_path()) {
+    clip_path.readFromMemory(details.clip_path().c_str(),

[vmpstr, 2015/10/26 17:46:17]

Does readFromMemory return some sort of a status code? If so, can you dcheck
that it succeeded?

[David Trainor- moved to gerrit, 2015/10/26 20:42:56]

It returns the bytes read to build the SkPath.  I can DCHECK that it's the same
as the size I'm passing in.

+                             details.clip_path().size());
+  }
+
+  SetNew(clip_path, clip_op, antialias);
+}
+
 void ClipPathDisplayItem::Raster(SkCanvas* canvas,
                                  const gfx::Rect& canvas_target_playback_rect,
                                  SkPicture::AbortCallback* callback) const {
   canvas->save();
   canvas->clipPath(clip_path_, clip_op_, antialias_);
 }
 
 void ClipPathDisplayItem::ProcessForBounds(
     DisplayItemListBoundsCalculator* calculator) const {
   calculator->AddStartingDisplayItem();
 }
 
 void ClipPathDisplayItem::AsValueInto(
     base::trace_event::TracedValue* array) const {
   array->AppendString(base::StringPrintf("ClipPathDisplayItem length: %d",
                                          clip_path_.countPoints()));
 }
 
 EndClipPathDisplayItem::EndClipPathDisplayItem() {
   DisplayItem::SetNew(true /* suitable_for_gpu_raster */, 0 /* op_count */,
                       0 /* external_memory_usage */);
 }
 
 EndClipPathDisplayItem::~EndClipPathDisplayItem() {
 }
 
+void EndClipPathDisplayItem::ToProtobuf(proto::DisplayItem* proto) {
+  proto->set_type(proto::DisplayItem::Type_EndClipPath);
+}
+
+void EndClipPathDisplayItem::FromProtobuf(const proto::DisplayItem& proto) {
+  DCHECK_EQ(proto::DisplayItem::Type_EndClipPath, proto.type());
+}
+
 void EndClipPathDisplayItem::Raster(
     SkCanvas* canvas,
     const gfx::Rect& canvas_target_playback_rect,
     SkPicture::AbortCallback* callback) const {
   canvas->restore();
 }
 
 void EndClipPathDisplayItem::ProcessForBounds(
     DisplayItemListBoundsCalculator* calculator) const {
   calculator->AddEndingDisplayItem();
 }
 
 void EndClipPathDisplayItem::AsValueInto(
     base::trace_event::TracedValue* array) const {
   array->AppendString("EndClipPathDisplayItem");
 }
 
 }  // namespace cc