Remove som GYP annotations, remove unused manifest.

gpu/gles2_conform_support/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.
 
 declare_args() {
   # Set to true to compile with the OpenGL ES 2.0 conformance tests.
   internal_gles2_conform_tests = false
 }
 
 config("gles2_conform_test_warnings") {
@@ skipping 21 matching lines @@
 
       # There are some implicit conversions from "int" to "char" in
       # GTFExtensionTestSurfacelessContext.c.
       "-Wno-constant-conversion",
     ]
   }
 }
 
 import("//testing/test.gni")
 
-# GYP version: gpu/gles2_conform_support/gles2_conform_support.gyp:gles2_conform_support
 executable("gles2_conform_support") {
   sources = [
     "gles2_conform_support.c",
     "native/egl_native.cc",
     "native/main.cc",
   ]
   defines = [
     "GLES2_CONFORM_SUPPORT_ONLY",
     "GTF_GLES20",
     "EGLAPI=",
@@ skipping 432 matching lines @@
 
   if (internal_gles2_conform_tests) {
     data_deps = [
       ":gles2_conform_test_windowless",
     ]
     deps += [ ":generate_gles2_conform_tests" ]
     sources += [ "$target_gen_dir/gles2_conform_test_autogen.cc" ]
     data += [ "//third_party/gles2_conform/GTF_ES/" ]
   }
 }