VideoCapture: migrate VideoCapture renderer-->host messages to mojo, part 2

content/common/video_capture_traits.h

+// Copyright 2016 The Chromium Authors. All rights reserved.

[Ken Rockot(use gerrit already), 2016/10/06 23:09:05]

nit: I would prefer we name this file more clearly to
video_capture_struct_traits.h. There are many type traits around the sources,
mojo StructTraits are just one kind

[mcasas, 2016/10/06 23:46:36]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_COMMON_VIDEO_CAPTURE_TRAITS_H_
+#define CONTENT_COMMON_VIDEO_CAPTURE_TRAITS_H_
+
+#include "content/common/video_capture.mojom.h"
+#include "media/base/video_capture_types.h"
+#include "mojo/common/common_custom_types_struct_traits.h"
+#include "services/video_capture/public/interfaces/video_capture_format.mojom.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<content::mojom::VideoCaptureParamsDataView,
+                    media::VideoCaptureParams> {
+  static media::VideoCaptureFormat requested_format(
+      const media::VideoCaptureParams& params) {
+    return params.requested_format;
+  }
+
+  static video_capture::mojom::ResolutionChangePolicy resolution_change_policy(
+      const media::VideoCaptureParams& params) {
+    return static_cast<video_capture::mojom::ResolutionChangePolicy>(

[Ken Rockot(use gerrit already), 2016/10/06 23:12:30]

Oops, just noticed this - you shouldn't need to do any casting here if you have
a typemap for ResolutionChangePolicy. You can just return
params.resolution_change_policy and use  media::ResolutionChangePolicy for the
return type. Same for media::PowerLineFrequency below.

[mcasas, 2016/10/06 23:46:36]

Done.

+        params.resolution_change_policy);
+  }
+
+  static video_capture::mojom::PowerLineFrequency power_line_frequency(
+      const media::VideoCaptureParams& params) {
+    return static_cast<video_capture::mojom::PowerLineFrequency>(
+        params.power_line_frequency);
+  }
+
+  static bool Read(content::mojom::VideoCaptureParamsDataView data,
+                   media::VideoCaptureParams* out);
+};
+}
+
+#endif  // CONTENT_COMMON_VIDEO_CAPTURE_TRAITS_H_