Add sysexEnabled readonly attribute to MIDIAccess

LayoutTests/webmidi/permission.html

Index: LayoutTests/webmidi/permission.html
diff --git a/LayoutTests/webmidi/permission.html b/LayoutTests/webmidi/permission.html
index d2b1625e282c64d2600fcde756e6b6b0c3b7b84f..5f3d80b0a452ac92d952b50abe31df5b7512265c 100644
--- a/LayoutTests/webmidi/permission.html
+++ b/LayoutTests/webmidi/permission.html
@@ -40,8 +40,12 @@ var acceptSysEx = function (next) {
     promise = navigator.requestMIDIAccess({sysex: true});
     shouldBeDefined("promise");
     shouldBeDefined("promise.then");
-    promise.then(function(access) {
+    promise.then(function(a) {
         testPassed("sysex permission request is successfully accepted.");
+        access = a;

[Takashi Toyoshima, 2014/03/24 11:38:10]

Make |access| global to be available from shouldBe().

+        shouldBeDefined("access");
+        shouldBeDefined("access.sysexEnabled");
+        shouldBe("access.sysexEnabled", "true");

[tkent, 2014/03/24 11:52:38]

shouldBe -> shouldBeTrue

         if (next)
             next();
         else