EME: Update MediaKeySystemConfiguration defaults; require non-empty capabilities

third_party/WebKit/public/platform/WebMediaKeySystemConfiguration.h

 // Copyright 2014 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 WebMediaKeySystemConfiguration_h
 #define WebMediaKeySystemConfiguration_h
 
 #include "public/platform/WebEncryptedMediaTypes.h"
 #include "public/platform/WebMediaKeySystemMediaCapability.h"
 #include "public/platform/WebVector.h"
 
 namespace blink {
 
 struct WebMediaKeySystemConfiguration {
   enum class Requirement {
     Required,
     Optional,
     NotAllowed,
   };
 
-  // As MediaKeySystemConfiguration is a dictionary, some members may be
-  // not-present. Because requestMediaKeySystemAccess() distinguishes empty
-  // from not-present, we require a presence flag for each member.
-  bool hasInitDataTypes = false;
+  WebString label;
   WebVector<WebEncryptedMediaInitDataType> initDataTypes;
-
-  bool hasAudioCapabilities = false;
   WebVector<WebMediaKeySystemMediaCapability> audioCapabilities;
-
-  bool hasVideoCapabilities = false;
   WebVector<WebMediaKeySystemMediaCapability> videoCapabilities;
-
-  // |distinctiveIdentifier| and |persistentState| are always present because
-  // they have default values.
   Requirement distinctiveIdentifier = Requirement::Optional;
   Requirement persistentState = Requirement::Optional;
-
-  bool hasSessionTypes = false;
   WebVector<WebEncryptedMediaSessionType> sessionTypes;
-
-  // |label| may be not-present, but we use a null string to represent that.
-  WebString label;
 };
 
 }  // namespace blink
 
 #endif  // WebMediaKeySystemConfiguration_h