Move chrome.usb to //extensions

chrome/common/extensions/api/api.gyp

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'targets': [
     {
       'target_name': 'chrome_api',
       'type': 'static_library',
       'sources': [
@@ skipping 101 matching lines @@
               'system_display.idl',
               'system_indicator.idl',
               'system_memory.idl',
               'system_network.idl',
               'system_private.json',
               'system_storage.idl',
               'tab_capture.idl',
               'tabs.json',
               'terminal_private.json',
               'types.json',
-              'usb.idl',
               'virtual_keyboard_private.json',
               'web_navigation.json',
               'web_request.json',
               # Despite the name, this API does not rely on any
               # WebRTC-specific bits and as such does not belong in
               # the enable_webrtc=0 section below.
               'webrtc_audio_private.idl',
               'webrtc_logging_private.idl',
               'webstore_private.json',
               'webview.json',
@@ skipping 56 matching lines @@
       'conditions': [
         ['chromeos==1', {
           'dependencies': [
             '<(DEPTH)/chrome/chrome.gyp:drive_proto',
           ],
         }],
       ],
     },
   ],
 }