Use sequence<T> instead of T[] where possible and document exceptions

third_party/WebKit/Source/core/events/MessageEvent.idl

Index: third_party/WebKit/Source/core/events/MessageEvent.idl
diff --git a/third_party/WebKit/Source/core/events/MessageEvent.idl b/third_party/WebKit/Source/core/events/MessageEvent.idl
index b8a5265f1bf63dfd26f009d69356e55c8f25e1ab..5c3a7e34eb4316c3979851519ea456043f42c863 100644
--- a/third_party/WebKit/Source/core/events/MessageEvent.idl
+++ b/third_party/WebKit/Source/core/events/MessageEvent.idl
@@ -37,6 +37,7 @@
     readonly attribute DOMString lastEventId;
     // TODO(bashi): |source| should be (WindowProxy or MessagePort)?
     readonly attribute EventTarget? source;
+    // TODO(foolip): |ports| should be FrozenArray<MessagePort>?
     readonly attribute MessagePort[]? ports;
     [RuntimeEnabled=suborigins] readonly attribute DOMString suborigin;
 
@@ -49,5 +50,5 @@
                                    [Default=Undefined] optional DOMString originArg,
                                    [Default=Undefined] optional DOMString lastEventIdArg,
                                    [Default=Undefined] optional Window sourceArg,
-                                   [Default=Undefined] optional MessagePort[] portsArg);
+                                   [Default=Undefined] optional sequence<MessagePort> portsArg);
 };