mash: Fix ShelfItem mojo struct; add enums and traits.

ash/public/cpp/shelf_struct_traits.cc

Index: ash/public/cpp/shelf_struct_traits.cc
diff --git a/ash/public/cpp/shelf_struct_traits.cc b/ash/public/cpp/shelf_struct_traits.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0864433f7ff34a6023514e6eba5bc0f5842ecf21
--- /dev/null
+++ b/ash/public/cpp/shelf_struct_traits.cc
@@ -0,0 +1,40 @@
+// Copyright 2017 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 "ash/public/cpp/shelf_struct_traits.h"
+
+#include "mojo/common/common_custom_types_struct_traits.h"
+#include "skia/public/interfaces/bitmap_skbitmap_struct_traits.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace mojo {
+
+using ShelfItemStructTraits =
+    StructTraits<ash::mojom::ShelfItemDataView, ash::ShelfItem>;
+
+// static
+const SkBitmap& ShelfItemStructTraits::image(const ash::ShelfItem& i) {
+  // TODO(crbug.com/655874): Remove this when we have a gfx::Image[Skia] mojom.
+  static const SkBitmap kNullSkBitmap;
+  return i.image.isNull() ? kNullSkBitmap : *i.image.bitmap();
+}
+
+// static
+bool ShelfItemStructTraits::Read(ash::mojom::ShelfItemDataView data,
+                                 ash::ShelfItem* out) {
+  SkBitmap image;
+  if (!data.ReadType(&out->type) || !data.ReadImage(&image) ||
+      !data.ReadStatus(&out->status) || !data.ReadAppId(&out->app_id) ||
+      !data.ReadTitle(&out->title)) {
+    return false;
+  }
+  out->id = data.shelf_id();
+  // TODO(crbug.com/655874): Support high-dpi images via gfx::Image[Skia] mojom.
+  out->image = gfx::ImageSkia::CreateFrom1xBitmap(image);
+  out->shows_tooltip = data.shows_tooltip();
+  out->pinned_by_policy = data.pinned_by_policy();
+  return true;
+}
+
+}  // namespace mojo