Don't assume output dir + "../.." == src/ in ui/gl/generate_bindings.py

ui/gl/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")
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 gl_binding_output_dir = target_gen_dir
@@ skipping 274 matching lines @@
     "$gl_binding_output_dir/gl_bindings_api_autogen_osmesa.h",
     "$gl_binding_output_dir/gl_bindings_autogen_wgl.cc",
     "$gl_binding_output_dir/gl_bindings_autogen_wgl.h",
     "$gl_binding_output_dir/gl_bindings_api_autogen_wgl.h",
     "$gl_binding_output_dir/gl_mock_autogen_gl.h",
   ]
 
   args = [
     "--header-paths=" +
         rebase_path("//third_party/khronos", root_build_dir) + ":" +
-        rebase_path("//third_party/mesa/src/include", root_build_dir),
+        rebase_path("//third_party/mesa/src/include", root_build_dir) + ":" +
+        rebase_path("//ui/gl", root_build_dir) + ":" +
+        rebase_path("//gpu", root_build_dir),
     rebase_path(gl_binding_output_dir, root_build_dir),
   ]
 }
 
 config("gl_unittest_utils_config") {
   include_dirs = [ gl_binding_output_dir ]
 }
 
 source_set("gl_unittest_utils") {
   sources = [
@@ skipping 15 matching lines @@
 
 if (is_android) {
   generate_jni("gl_jni_headers") {
     sources = [
       "../android/java/src/org/chromium/ui/gl/SurfaceTextureListener.java",
       "../android/java/src/org/chromium/ui/gl/SurfaceTexturePlatformWrapper.java",
     ]
     jni_package = "ui/gl"
   }
 }