Web MIDI: remove deprecated Blink APIs

This is the last step to update the Blink APIs.

In the first change, https://codereview.chromium.org/649683006/,
new APIs having isActive flags are added.

In the second change, https://codereview.chromium.org/661323002/,
callers in Chromium that uses old APIs are modified to use new APIs.

In this third change, deprecated APIs are removed.

BUG=279097

Review URL: https://codereview.chromium.org/662253002

git-svn-id: svn://svn.chromium.org/blink/trunk@184140 bbb929c8-8fbe-4397-9dbb-9b2b20218538