Add support for the Projection element

It's a part of the Google Spatial Media V2 spec:
https://github.com/google/spatial-media/blob/master/docs/spherical-video-v2-rfc.md

Change-Id: I52f05e34b19239af09774da2f88eb584a0bfa628

webm_parser/src/projection_parser.h

@@ -0,0 +1,40 @@
+// Copyright (c) 2016 The WebM project authors. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS.  All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+#ifndef SRC_PROJECTION_PARSER_H_
+#define SRC_PROJECTION_PARSER_H_
+
+#include "src/byte_parser.h"
+#include "src/float_parser.h"
+#include "src/int_parser.h"
+#include "src/master_value_parser.h"
+#include "webm/dom_types.h"
+#include "webm/id.h"
+
+namespace webm {
+
+// Spec reference:
+// https://github.com/google/spatial-media/blob/master/docs/spherical-video-v2-rfc.md#projection-master-element
+class ProjectionParser : public MasterValueParser<Projection> {
+ public:
+  ProjectionParser()
+      : MasterValueParser(
+            MakeChild<IntParser<ProjectionType>>(Id::kProjectionType,
+                                                 &Projection::type),
+            MakeChild<BinaryParser>(Id::kProjectionPrivate,
+                                    &Projection::projection_private),
+            MakeChild<FloatParser>(Id::kProjectionPoseYaw,
+                                   &Projection::pose_yaw),
+            MakeChild<FloatParser>(Id::kProjectionPosePitch,
+                                   &Projection::pose_pitch),
+            MakeChild<FloatParser>(Id::kProjectionPoseRoll,
+                                   &Projection::pose_roll)) {}
+};
+
+}  // namespace webm
+
+#endif  // SRC_PROJECTION_PARSER_H_

webm_parser/src/video_parser.h

@@ -16,6 +16,7 @@
 #include "src/float_parser.h"
 #include "src/int_parser.h"
 #include "src/master_value_parser.h"
+#include "src/projection_parser.h"
 #include "webm/callback.h"
 #include "webm/dom_types.h"
 #include "webm/id.h"
@@ -58,7 +59,8 @@ class VideoParser : public MasterValueParser<Video> {
             MakeChild<IntParser<AspectRatioType>>(Id::kAspectRatioType,
                                                   &Video::aspect_ratio_type),
             MakeChild<FloatParser>(Id::kFrameRate, &Video::frame_rate),
-            MakeChild<ColourParser>(Id::kColour, &Video::colour)) {}
+            MakeChild<ColourParser>(Id::kColour, &Video::colour),
+            MakeChild<ProjectionParser>(Id::kProjection, &Video::projection)) {}
 
   Status Init(const ElementMetadata& metadata,
               std::uint64_t max_size) override {