Revert broken Linux hidpi changes.

chrome/browser/ui/libgtk2ui/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.
 
 assert(is_linux, "This file should only be referenced on Linux")
 
 import("//build/config/features.gni")
 
 component("libgtk2ui") {
   sources = [
@@ skipping 43 matching lines @@
     "x11_input_method_context_impl_gtk2.cc",
     "x11_input_method_context_impl_gtk2.h",
   ]
 
   if (use_gconf) {
     sources += [
       "gconf_listener.cc",
       "gconf_listener.h",
     ]
   }
-  defines = [
-    "LIBGTK2UI_IMPLEMENTATION",
-
-    # g_settings_list_schemas is deprecated, but this function is not
-    # available on earlier version that we still need to support.
-    # See build/config/linux/BUILD.gn:gio_config for details.
-    "GLIB_DISABLE_DEPRECATION_WARNINGS",
-  ]
+  defines = [ "LIBGTK2UI_IMPLEMENTATION" ]
 
   configs += [
     "//build/config/linux:gconf",
     "//printing:cups",
   ]
 
   # GTK2 pulls pangoft2 as dependency, and pangoft2 depends on harfbuzz.
   # To avoid missing indirectly referenced harfbuzz symbols from pango,
   # some hack is required when bundled harfbuzz is used and component build is
   # disabled.
@@ skipping 43 matching lines @@
     "//ui/events:events_base",
     "//ui/gfx",
     "//ui/gfx/x",
     "//ui/native_theme",
     "//ui/resources",
     "//ui/shell_dialogs",
     "//ui/strings",
     "//ui/views",
   ]
 }