Add onconnect and ondisconnect events to navigator.usb.

This patch updates USB.idl to add these two events, making it an
EventTarget. WebUSBClient still needs to be updated to support
delivering these events to Blink.

BUG=492204

Review URL: https://codereview.chromium.org/1291753004

git-svn-id: svn://svn.chromium.org/blink/trunk@200912 bbb929c8-8fbe-4397-9dbb-9b2b20218538
10 files changed
tree: 835b605706c70508802bfe06a55f59bcb918553b
  1. third_party/