Remove comments regarding deleted mojo_examlpes.gypi.

mojo/examples/keyboard/BUILD.gn

 # Copyright 2014 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/ui.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 assert(use_aura)
 
-# GYP version: mojo/mojo_examples.gypi:mojo_keyboard
 shared_library("keyboard") {
   output_name = "mojo_keyboard"
 
   sources = [
     "keyboard_delegate.h",
     "keyboard_view.cc",
     "keyboard_view.h",
     "keyboard.cc",
     "keys.cc",
     "keys.h",
@@ skipping 20 matching lines @@
     "//ui/compositor",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/resources",
     "//ui/resources:ui_test_pak",
     "//ui/views",
     "//url",
   ]
 }
 
-# GYP version: mojo/mojo_examples.gypi:mojo_keyboard_bindings
 mojom("bindings") {
   sources = [ "keyboard.mojom" ]
 }