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;
     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;
 
+    // As |sessionTypes| is optional, we require a presence flag for it.
     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