Remove som GYP annotations, remove unused manifest.

gpu/gles2_conform_support/egl/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.
 
-# GYP version: gpu/gles2_conform_support/gles_conform_support.gyp:egl_native
 source_set("egl") {
   output_name = "egl_native"
   sources = [
     "config.cc",
     "config.h",
     "context.cc",
     "context.h",
     "display.cc",
     "display.h",
     "egl.cc",
@@ skipping 18 matching lines @@
     "//gpu/command_buffer/client:gles2_c_lib_nocheck",
     "//gpu/command_buffer/client:gles2_implementation_no_check",
     "//gpu/command_buffer/common:gles2_utils",
     "//gpu/command_buffer/service",
     "//ui/base",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
   ]
 }