Define EnumTraits for content::MediaDeviceType

This CL introduces Mojom enum for content::MediaDeviceType and removes
its IPC_ENUM_TRAITS in favor of EnumTraits.
This is in preparation for migration of MediaDevices.enumerateDevices()
processing from content to Blink.

Bug: 764680
Change-Id: I5e3c96adb7fd96e1d0ea41dff933ecac017228fa
Reviewed-on: https://chromium-review.googlesource.com/806054Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Chandan Padhi <c.padhi@samsung.com>
Cr-Commit-Position: refs/heads/master@{#521971}

content/common/DEPS

@@ -52,6 +52,7 @@ include_rules = [
   "+third_party/WebKit/public/platform/modules/fetch/fetch_api_request.mojom.h",
   "+third_party/WebKit/public/platform/modules/indexeddb/WebIDBTypes.h",
   "+third_party/WebKit/public/platform/modules/mediasession/media_session.mojom.h",
+  "+third_party/WebKit/public/platform/modules/mediastream/media_devices.mojom.h",
   "+third_party/WebKit/public/platform/modules/permissions/permission.mojom.h",
   "+third_party/WebKit/public/platform/modules/permissions/permission_status.mojom.h",
   "+third_party/WebKit/public/platform/modules/presentation/presentation.mojom.h",

content/common/media/media_devices.typemap

@@ -4,7 +4,13 @@
 
 mojom = "//third_party/WebKit/public/platform/modules/mediastream/media_devices.mojom"
 public_headers = [ "//content/common/media/media_devices.h" ]
-traits_headers = [ "//content/common/media/media_devices_param_traits.h" ]
+traits_headers = [
+  "//content/common/media/media_devices_param_traits.h",
+  "//content/common/media/media_devices_typemap_traits.h",
+]
+sources = [
+  "//content/common/media/media_devices_typemap_traits.cc",
+]
 type_mappings = [
   "blink.mojom.MediaDeviceType=content::MediaDeviceType",
   "blink.mojom.MediaDeviceInfo=content::MediaDeviceInfo",

content/common/media/media_devices_param_traits.h

@@ -11,9 +11,6 @@
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 
-IPC_ENUM_TRAITS_MAX_VALUE(content::MediaDeviceType,
-                          content::NUM_MEDIA_DEVICE_TYPES - 1)
-
 IPC_STRUCT_TRAITS_BEGIN(content::MediaDeviceInfo)
   IPC_STRUCT_TRAITS_MEMBER(device_id)
   IPC_STRUCT_TRAITS_MEMBER(label)

content/common/media/media_devices_typemap_traits.cc

+// 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 "content/common/media/media_devices_typemap_traits.h"
+
+#include "base/logging.h"
+
+namespace mojo {
+
+// static
+blink::mojom::MediaDeviceType
+EnumTraits<blink::mojom::MediaDeviceType, content::MediaDeviceType>::ToMojom(
+    content::MediaDeviceType type) {
+  switch (type) {
+    case content::MediaDeviceType::MEDIA_DEVICE_TYPE_AUDIO_INPUT:
+      return blink::mojom::MediaDeviceType::MEDIA_AUDIO_INPUT;
+    case content::MediaDeviceType::MEDIA_DEVICE_TYPE_VIDEO_INPUT:
+      return blink::mojom::MediaDeviceType::MEDIA_VIDEO_INPUT;
+    case content::MediaDeviceType::MEDIA_DEVICE_TYPE_AUDIO_OUTPUT:
+      return blink::mojom::MediaDeviceType::MEDIA_AUDIO_OUTPUT;
+    default:
+      break;
+  }
+  NOTREACHED();
+  return blink::mojom::MediaDeviceType::NUM_MEDIA_DEVICE_TYPES;
+}
+
+// static
+bool EnumTraits<blink::mojom::MediaDeviceType, content::MediaDeviceType>::
+    FromMojom(blink::mojom::MediaDeviceType input,
+              content::MediaDeviceType* out) {
+  switch (input) {
+    case blink::mojom::MediaDeviceType::MEDIA_AUDIO_INPUT:
+      *out = content::MediaDeviceType::MEDIA_DEVICE_TYPE_AUDIO_INPUT;
+      return true;
+    case blink::mojom::MediaDeviceType::MEDIA_VIDEO_INPUT:
+      *out = content::MediaDeviceType::MEDIA_DEVICE_TYPE_VIDEO_INPUT;
+      return true;
+    case blink::mojom::MediaDeviceType::MEDIA_AUDIO_OUTPUT:
+      *out = content::MediaDeviceType::MEDIA_DEVICE_TYPE_AUDIO_OUTPUT;
+      return true;
+    default:
+      break;
+  }
+  NOTREACHED();
+  return false;
+}
+
+}  // namespace mojo

content/common/media/media_devices_typemap_traits.h

+// 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.
+
+#ifndef CONTENT_COMMON_MEDIA_MEDIA_DEVICES_TYPEMAP_TRAITS_H_
+#define CONTENT_COMMON_MEDIA_MEDIA_DEVICES_TYPEMAP_TRAITS_H_
+
+#include "content/common/media/media_devices.h"
+#include "third_party/WebKit/public/platform/modules/mediastream/media_devices.mojom.h"
+
+namespace mojo {
+
+template <>
+struct EnumTraits<blink::mojom::MediaDeviceType, content::MediaDeviceType> {
+  static blink::mojom::MediaDeviceType ToMojom(content::MediaDeviceType type);
+
+  static bool FromMojom(blink::mojom::MediaDeviceType input,
+                        content::MediaDeviceType* out);
+};
+
+}  // namespace mojo
+
+#endif  // CONTENT_COMMON_MEDIA_MEDIA_DEVICES_TYPEMAP_TRAITS_H_
\ No newline at end of file

third_party/WebKit/public/platform/modules/mediastream/media_devices.mojom

@@ -7,23 +7,21 @@ module blink.mojom;
 import "media/capture/mojo/video_capture_types.mojom";
 import "media/mojo/interfaces/audio_parameters.mojom";
 
-[Native]
-enum MediaDeviceType;
-
 [Native]
 struct MediaDeviceInfo;
 
+enum MediaDeviceType {
+  MEDIA_AUDIO_INPUT,
+  MEDIA_VIDEO_INPUT,
+  MEDIA_AUDIO_OUTPUT,
+  NUM_MEDIA_DEVICE_TYPES
+};
+
 // The values for this enum match the ones defined in
 // https://w3c.github.io/mediacapture-main/#def-constraint-facingMode
 // with the addition of NONE, which would map to the empty string in
 // JavaScript.
-enum FacingMode {
-  NONE,
-  USER,
-  ENVIRONMENT,
-  LEFT,
-  RIGHT
-};
+enum FacingMode { NONE, USER, ENVIRONMENT, LEFT, RIGHT };
 
 struct VideoInputDeviceCapabilities {
   string device_id;
@@ -41,7 +39,7 @@ struct AudioInputDeviceCapabilities {
 // notifications.
 interface MediaDevicesDispatcherHost {
   // The reply always contains NUM_MEDIA_DEVICE_TYPES elements.
-  // The result is indexed by device type as defined in 
+  // The result is indexed by device type as defined in
   // content/common/media/media_devices.h.
   EnumerateDevices(bool request_audio_input,
                    bool request_video_input,