Use mojo typemap to simplify the code using DmabufPlane

components/arc/common/video_accelerator.typemap

Index: components/arc/common/video_accelerator.typemap
diff --git a/components/arc/common/video_accelerator.typemap b/components/arc/common/video_accelerator.typemap
new file mode 100644
index 0000000000000000000000000000000000000000..3461d8658d1af98b453d912ace2c7fe0d37550f5
--- /dev/null
+++ b/components/arc/common/video_accelerator.typemap
@@ -0,0 +1,12 @@
+# 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.
+
+mojom = "//components/arc/common/video_accelerator.mojom"
+public_headers = [ "//components/arc/video_accelerator/video_accelerator.h" ]
+traits_headers =
+    [ "//components/arc/video_accelerator/video_accelerator_struct_traits.h" ]
+sources = [
+  "//components/arc/video_accelerator/video_accelerator_struct_traits.cc",
+]
+type_mappings = [ "arc.mojom.ArcVideoAcceleratorDmabufPlane=arc::ArcVideoAcceleratorDmabufPlane[move_only]" ]