Web MIDI: remove old Windows backend

media/midi/BUILD.gn

 # Copyright 2015 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.
 
 import("//build/config/android/config.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
@@ skipping 126 matching lines @@
       "CoreFoundation.framework",
       "CoreMIDI.framework",
     ]
   }
 
   if (is_win) {
     deps += [ "//device/usb" ]
     sources += [
       "dynamically_initialized_midi_manager_win.cc",
       "dynamically_initialized_midi_manager_win.h",
-      "midi_manager_win.cc",
-      "midi_manager_win.h",
       "midi_manager_winrt.cc",
       "midi_manager_winrt.h",
     ]
 
     # This library is included in base in static builds.
     if (is_component_build) {
       libs += [ "cfgmgr32.lib" ]
     }
   }
 
@@ skipping 50 matching lines @@
     libs = [ "CoreMIDI.framework" ]
   }
 
   if (use_alsa && use_udev) {
     sources += [ "midi_manager_alsa_unittest.cc" ]
   }
 
   # This target should not require the Chrome executable to run.
   assert_no_deps = [ "//chrome" ]
 }