Don't perform the default action when keyCode is 229.

The keyCode of 229 signifies that this event is being dispatched during
an IME composition. Previously keyIdentifier ended up being ProcessKey but
with the converstion to key events this started to be processed.

Put a conditional around the event to ensure that keyCode == 229 events
are discarded. This will eventually be replaced with the isComposing
flag that should be added to KeyboardEvent.

BUG=620794, 622158

Review-Url: https://codereview.chromium.org/2121843002
Cr-Commit-Position: refs/heads/master@{#403737}
1 file changed