Use extension-based file picker from CrOS for Aura builds.

build/common.gypi

 # Copyright (c) 2011 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 244 matching lines @@
           'use_titlecase_in_grd_files%': 1,
         }],
 
         # Enable some hacks to support Flapper only on Chrome OS.
         ['chromeos==1', {
           'enable_flapper_hacks%': 1,
         }, {
           'enable_flapper_hacks%': 0,
         }],
 
-        # Enable file manager extension by default on Chrome OS.
-        ['chromeos==1', {
+        # Enable file manager extension on Chrome OS, Touch, PureView, Aura.
+        ['chromeos==1 or touchui==1 or use_only_pure_views==1 or use_aura==1', {
           'file_manager_extension%': 1,
         }, {
           'file_manager_extension%': 0,
         }],
 
         # Enable WebUI TaskManager only on Chrome OS, Touch or PureView.
         ['chromeos==1 or touchui==1 or use_only_pure_views==1 or use_aura==1', {
           'webui_task_manager%': 1,
         }, {
           'webui_task_manager%': 0,
@@ skipping 2113 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }