Use mojo typemap to simplify the code using DmabufPlane

components/arc/video_accelerator/video_accelerator_struct_traits.h

Index: components/arc/video_accelerator/video_accelerator_struct_traits.h
diff --git a/components/arc/video_accelerator/video_accelerator_struct_traits.h b/components/arc/video_accelerator/video_accelerator_struct_traits.h
new file mode 100644
index 0000000000000000000000000000000000000000..251a7a06af5cf53fd747c8712c384c45176a6954
--- /dev/null
+++ b/components/arc/video_accelerator/video_accelerator_struct_traits.h
@@ -0,0 +1,32 @@
+// 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.
+
+#ifndef COMPONENT_ARC_COMMON_VIDEO_ACCELERATOR_STRUCT_TRAITS_H_
+#define COMPONENT_ARC_COMMON_VIDEO_ACCELERATOR_STRUCT_TRAITS_H_
+
+#include "components/arc/common/video_accelerator.mojom.h"
+#include "components/arc/video_accelerator/video_accelerator.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<arc::mojom::ArcVideoAcceleratorDmabufPlaneDataView,
+                    ::arc::ArcVideoAcceleratorDmabufPlane> {

[Yusuke Sato, 2016/11/29 21:34:28]

(here and elsewhere)
The leading :: seems redundant. Since this function is not in chromeos::arc::,
you can remove the leading ::.

[yoshiki, 2016/11/30 17:25:44]

Done.

+  static uint32_t offset(const ::arc::ArcVideoAcceleratorDmabufPlane& r) {
+    return r.offset;
+  }
+  static uint32_t stride(const ::arc::ArcVideoAcceleratorDmabufPlane& r) {
+    return r.stride;
+  }
+
+  static bool Read(arc::mojom::ArcVideoAcceleratorDmabufPlaneDataView data,
+                   ::arc::ArcVideoAcceleratorDmabufPlane* out) {
+    out->offset = data.offset();
+    out->stride = data.stride();

[Luis Héctor Chávez, 2016/11/29 18:25:36]

here you can check if either the stride or offset are invalid and log + return
false.

[yoshiki, 2016/11/30 17:25:44]

Done.

+    return true;
+  }
+};
+}

[Luis Héctor Chávez, 2016/11/29 18:25:36]

nit: empty line before to preserve symmetry.

[Yusuke Sato, 2016/11/29 21:34:28]

same. // namespace mojo

[yoshiki, 2016/11/30 17:25:44]

Done.

+
+#endif  // COMPONENT_ARC_COMMON_VIDEO_ACCELERATOR_STRUCT_TRAITS_H_