Drop LegacyInterfaceTypeChecking for SpeechSynthesisUtterance

third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl

Index: third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl
diff --git a/third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl b/third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl
index 8a0527903bde4af770f36585c5ba10327d9f68af..1021a743d469d1fb2964824dbd744d69be9c8dcd 100644
--- a/third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl
+++ b/third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl
@@ -23,6 +23,8 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+// https://dvcs.w3.org/hg/speech-api/raw-file/tip/webspeechapi.html#tts-section
+
 [
     Constructor(optional DOMString text = null),
     ConstructorCallWith=ExecutionContext,
@@ -30,7 +32,7 @@
 ] interface SpeechSynthesisUtterance : EventTarget {
     attribute DOMString text;
     attribute DOMString lang;
-    [LegacyInterfaceTypeChecking] attribute SpeechSynthesisVoice voice;
+    attribute SpeechSynthesisVoice? voice;
     attribute float volume;
     attribute float rate;
     attribute float pitch;