Introduce Promises.

Source/core/dom/PromiseResolver.idl

Index: Source/core/dom/PromiseResolver.idl
diff --git a/Source/modules/webmidi/MIDIErrorCallback.idl b/Source/core/dom/PromiseResolver.idl
similarity index 95%
copy from Source/modules/webmidi/MIDIErrorCallback.idl
copy to Source/core/dom/PromiseResolver.idl
index 0591bf6715e14bf85426c3cfb82fc2aedf25918d..86fe30751c847623f955f1eece26482ceeb11e4a 100644
--- a/Source/modules/webmidi/MIDIErrorCallback.idl
+++ b/Source/core/dom/PromiseResolver.idl
@@ -28,6 +28,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-callback interface MIDIErrorCallback {
-    boolean handleEvent(DOMError error);
+[
+   EnabledAtRuntime=promise

[do-not-use, 2013/06/21 15:04:58]

Although it does not impact the generated code, Promise should technically use a
capital P here I believe.

[yhirano, 2013/06/24 03:33:34]

Really? I saw IDL files having EnabledAtRuntime in Source/core/dom. The flag
name starts with a lower letter, in most cases.

+] interface PromiseResolver {
 };