[blimp] Add SkPicture caching support.

cc/blimp/picture_data_conversions.cc

Index: cc/blimp/picture_data_conversions.cc
diff --git a/cc/blimp/picture_data_conversions.cc b/cc/blimp/picture_data_conversions.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d54835f6568a06ff6773312bb195357794fe67da
--- /dev/null
+++ b/cc/blimp/picture_data_conversions.cc
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+// Copyright 2016 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/blimp/picture_data_conversions.h"
+
+#include <memory>
+
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "cc/proto/display_item.pb.h"
+#include "cc/proto/layer_tree_host.pb.h"
+
+namespace cc {
+namespace proto {
+
+void PictureDataVectorToSkPicturesProto(
+    const std::vector<PictureData>& cache_update,
+    SkPictures* proto_pictures) {
+  for (const PictureData& picture : cache_update) {
+    proto::SkPictureData* picture_data = proto_pictures->add_pictures();
+    proto::SkPictureID* picture_id = picture_data->mutable_id();
+    picture_id->set_unique_id(picture.unique_id);
+    picture_data->set_payload(picture.data->data(), picture.data->size());
+  }
+}
+
+std::vector<PictureData> SkPicturesProtoToPictureDataVector(
+    const SkPictures& proto_pictures) {
+  std::vector<PictureData> result;
+  for (int i = 0; i < proto_pictures.pictures_size(); ++i) {
+    SkPictureData proto_picture = proto_pictures.pictures(i);
+    DCHECK(proto_picture.has_id());
+    DCHECK(proto_picture.id().has_unique_id());
+    DCHECK(proto_picture.has_payload());
+    PictureData picture_data(
+        proto_picture.id().unique_id(),
+        SkData::MakeWithCopy(proto_picture.payload().data(),
+                             proto_picture.payload().size()));
+    result.push_back(picture_data);
+  }
+  return result;
+}
+
+}  // namespace proto
+}  // namespace cc