Put 'tools' directory at front of import path.

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 argparse
@@ skipping 12 matching lines @@
 
 sys.path.insert(0, os.path.join(chrome_src, 'tools', 'gyp', 'pylib'))
 import gyp
 
 # Assume this file is in a one-level-deep subdirectory of the source root.
 SRC_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 
 # Add paths so that pymod_do_main(...) can import files.
 sys.path.insert(1, os.path.join(chrome_src, 'android_webview', 'tools'))
 sys.path.insert(1, os.path.join(chrome_src, 'build', 'android', 'gyp'))
-sys.path.insert(1, os.path.join(chrome_src, 'tools'))
-sys.path.insert(1, os.path.join(chrome_src, 'tools', 'generate_shim_headers'))
-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, 'chromecast', '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'))
+sys.path.insert(1, os.path.join(chrome_src, 'tools'))
+sys.path.insert(1, os.path.join(chrome_src, 'tools', 'generate_shim_headers'))
+sys.path.insert(1, os.path.join(chrome_src, 'tools', 'grit'))
 
 # 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 268 matching lines @@
 
   if not use_analyzer:
     vs2013_runtime_dll_dirs = vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
     if vs2013_runtime_dll_dirs:
       x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
       vs_toolchain.CopyVsRuntimeDlls(
         os.path.join(chrome_src, GetOutputDirectory()),
         (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)