Do not need to find depot_tools and run GN when GYP_GENERATORS=make

build/gyp_chromium

 #!/usr/bin/env python
 
 # 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.
 
 # This script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import glob
@@ skipping 21 matching lines @@
 sys.path.insert(1, os.path.join(chrome_src, 'tools', 'grit'))
 sys.path.insert(1, os.path.join(chrome_src, 'chrome', 'tools', 'build'))
 sys.path.insert(1, os.path.join(chrome_src, 'native_client', 'build'))
 sys.path.insert(1, os.path.join(chrome_src, 'native_client_sdk', 'src',
     'build_tools'))
 sys.path.insert(1, os.path.join(chrome_src, 'remoting', 'tools', 'build'))
 sys.path.insert(1, os.path.join(chrome_src, 'third_party', 'liblouis'))
 sys.path.insert(1, os.path.join(chrome_src, 'third_party', 'WebKit',
     'Source', 'build', 'scripts'))
 
-import find_depot_tools
+if os.environ.get('GYP_GENERATORS') != 'make':
+  import find_depot_tools
 
 # On Windows, Psyco shortens warm runs of build/gyp_chromium by about
 # 20 seconds on a z600 machine with 12 GB of RAM, from 90 down to 70
 # seconds.  Conversely, memory usage of build/gyp_chromium with Psyco
 # maxes out at about 158 MB vs. 132 MB without it.
 #
 # Psyco uses native libraries, so we need to load a different
 # installation depending on which OS we are running under. It has not
 # been tested whether using Psyco on our Mac and Linux builds is worth
 # it (the GYP running time is a lot shorter, so the JIT startup cost
@@ skipping 414 matching lines @@
       print('Using automatic toolchain in %s (%s edition).' % (
                 toolchain, 'Pro' if version_is_pro else 'Express'))
 
   # If CHROMIUM_GYP_SYNTAX_CHECK is set to 1, it will invoke gyp with --check
   # to enfore syntax checking.
   syntax_check = os.environ.get('CHROMIUM_GYP_SYNTAX_CHECK')
   if syntax_check and int(syntax_check):
     args.append('--check')
 
   supplemental_includes = GetSupplementalFiles()
-  if not RunGN(supplemental_includes):
-    sys.exit(1)
+  if os.environ.get('GYP_GENERATORS') != 'make':
+    if not RunGN(supplemental_includes):
+      sys.exit(1)
   args.extend(
       ['-I' + i for i in additional_include_files(supplemental_includes, args)])
 
   args.extend(['-D', 'gyp_output_dir=' + GetOutputDirectory()])
 
   print 'Updating projects from gyp files...'
   sys.stdout.flush()
 
   # Off we go...
   gyp_rc = gyp.main(args)
 
   # Check for landmines (reasons to clobber the build). This must be run here,
   # rather than a separate runhooks step so that any environment modifications
   # from above are picked up.
   print 'Running build/landmines.py...'
   subprocess.check_call(
       [sys.executable, os.path.join(script_dir, 'landmines.py')])
 
   if vs2013_runtime_dll_dirs:
     CopyVsRuntimeDlls(GetOutputDirectory(), vs2013_runtime_dll_dirs)
 
   sys.exit(gyp_rc)