Revert 241524 "Web MIDI: minimum support for Linux and Chrome OS"

Broke Chromium OS ASAN bots.
http://build.chromium.org/p/chromium.memory/builders/Chromium%20OS%20%28x86%29%20ASAN/builds/7556

> Web MIDI: minimum support for Linux and Chrome OS
> 
> This change enables Web MIDI API on Linux and Chrome OS.
> Only Sending functionality works with this first experimental change.
> 
> BUG=303601
> 
> Review URL: https://codereview.chromium.org/111443005

TBR=toyoshim@chromium.org

Review URL: https://codereview.chromium.org/107953003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241532 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241532