Introduce the chroot_cmd flag that contains the command line prefix for running in a chrooted envir…

build/common.gypi

 # Copyright (c) 2012 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 265 matching lines @@
       'python_ver%': '2.6',
 
       # Set NEON compilation flags.
       'arm_neon%': 1,
 
       # Detect NEON support at run-time.
       'arm_neon_optional%': 0,
 
       # The system root for cross-compiles. Default: none.
       'sysroot%': '',
+      'chroot_cmd%': '',
 
       # The system libdir used for this ABI.
       'system_libdir%': 'lib',
 
       # On Linux, we build with sse2 for Chromium builds.
       'disable_sse2%': 0,
 
       # Use libjpeg-turbo as the JPEG codec used by Chromium.
       'use_libjpeg_turbo%': 1,
 
@@ skipping 605 matching lines @@
     'image_loader_extension%': '<(image_loader_extension)',
     'fastbuild%': '<(fastbuild)',
     'dcheck_always_on%': '<(dcheck_always_on)',
     'logging_like_official_build%': '<(logging_like_official_build)',
     'tracing_like_official_build%': '<(tracing_like_official_build)',
     'python_ver%': '<(python_ver)',
     'arm_version%': '<(arm_version)',
     'arm_neon%': '<(arm_neon)',
     'arm_neon_optional%': '<(arm_neon_optional)',
     'sysroot%': '<(sysroot)',
+    'chroot_cmd%': '<(chroot_cmd)',
     'system_libdir%': '<(system_libdir)',
     'component%': '<(component)',
     'use_titlecase_in_grd_files%': '<(use_titlecase_in_grd_files)',
     'use_third_party_translations%': '<(use_third_party_translations)',
     'remoting%': '<(remoting)',
     'enable_one_click_signin%': '<(enable_one_click_signin)',
     'enable_webrtc%': '<(enable_webrtc)',
     'chromium_win_pch%': '<(chromium_win_pch)',
     'configuration_policy%': '<(configuration_policy)',
     'safe_browsing%': '<(safe_browsing)',
@@ skipping 3992 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',
   },
 }