1 files changed, 59 insertions, 0 deletions
diff --git a/chromium/media/base/media_log_type_enforcement.h b/chromium/media/base/media_log_type_enforcement.h
new file mode 100644
index 00000000000..8404e00a23f
--- /dev/null
+++ b/chromium/media/base/media_log_type_enforcement.h
@@ -0,0 +1,59 @@
+// Copyright 2019 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 MEDIA_BASE_MEDIA_LOG_TYPE_ENFORCEMENT_H_
+#define MEDIA_BASE_MEDIA_LOG_TYPE_ENFORCEMENT_H_
+
+#include "media/base/media_serializers.h"
+
+namespace media {
+
+namespace internal {
+enum class UnmatchableType {};
+}  // namespace internal
+
+// Forward declare the enums.
+enum class MediaLogProperty;
+enum class MediaLogEvent;
+
+// Allow only specific types for an individual property.
+template <MediaLogProperty PROP, typename T>
+struct MediaLogPropertyTypeSupport {};
+
+// Allow only specific types for an individual event.
+// However unlike Property, T is not required, so we default it to some
+// unmatchable type that will never be passed as an argument accidentally.
+template <MediaLogEvent EVENT, typename T = internal::UnmatchableType>
+struct MediaLogEventTypeSupport {};
+
+// Lets us define the supported type in a single line in media_log_properties.h.
+#define MEDIA_LOG_PROPERTY_SUPPORTS_TYPE(PROPERTY, TYPE)                 \
+  template <>                                                            \
+  struct MediaLogPropertyTypeSupport<MediaLogProperty::PROPERTY, TYPE> { \
+    static base::Value Convert(const TYPE& type) {                       \
+      return MediaSerialize<TYPE>(type);                                 \
+    }                                                                    \
+  }
+
+#define MEDIA_LOG_EVENT_NAMED_DATA(EVENT, TYPE, DISPLAY)           \
+  template <>                                                      \
+  struct MediaLogEventTypeSupport<MediaLogEvent::EVENT, TYPE> {    \
+    static void AddExtraData(base::Value* params, const TYPE& t) { \
+      DCHECK(params);                                              \
+      params->SetKey(DISPLAY, MediaSerialize<TYPE>(t));            \
+    }                                                              \
+    static std::string TypeName() { return #EVENT; }               \
+  }
+
+// Specifically do not create the Convert or DisplayName methods
+#define MEDIA_LOG_EVENT_TYPELESS(EVENT)                   \
+  template <>                                             \
+  struct MediaLogEventTypeSupport<MediaLogEvent::EVENT> { \
+    static std::string TypeName() { return #EVENT; }      \
+    static void AddExtraData(base::Value* params) {}      \
+  }
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_MEDIA_LOG_TYPE_ENFORCEMENT_H_