Update from https://crrev.com/304121

tools/clang/scripts/update.py

 #!/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.
 
 """Windows can't run .sh files, so this is a Python implementation of
 update.sh. This script should replace update.sh on all platforms eventually."""
 
 import os
 import re
@@ skipping 14 matching lines @@
   LLVM_WIN_REVISION = '217738'
 
 # Path constants. (All of these should be absolute paths.)
 THIS_DIR = os.path.abspath(os.path.dirname(__file__))
 CHROMIUM_DIR = os.path.abspath(os.path.join(THIS_DIR, '..', '..', '..'))
 LLVM_DIR = os.path.join(CHROMIUM_DIR, 'third_party', 'llvm')
 LLVM_BUILD_DIR = os.path.join(CHROMIUM_DIR, 'third_party', 'llvm-build',
                               'Release+Asserts')
 COMPILER_RT_BUILD_DIR = os.path.join(LLVM_BUILD_DIR, '32bit-compiler-rt')
 CLANG_DIR = os.path.join(LLVM_DIR, 'tools', 'clang')
+LLD_DIR = os.path.join(LLVM_DIR, 'tools', 'lld')
 COMPILER_RT_DIR = os.path.join(LLVM_DIR, 'projects', 'compiler-rt')
 STAMP_FILE = os.path.join(LLVM_BUILD_DIR, 'cr_build_revision')
 
 LLVM_REPO_URL='https://llvm.org/svn/llvm-project'
 if 'LLVM_REPO_URL' in os.environ:
   LLVM_REPO_URL = os.environ['LLVM_REPO_URL']
 
 
 def ReadStampFile():
   """Return the contents of the stamp file, or '' if it doesn't exist."""
@@ skipping 127 matching lines @@
     return 0
 
   AddCMakeToPath()
   ClobberChromiumBuildFiles()
 
   # Reset the stamp file in case the build is unsuccessful.
   WriteStampFile('')
 
   Checkout('LLVM', LLVM_REPO_URL + '/llvm/trunk', LLVM_DIR)
   Checkout('Clang', LLVM_REPO_URL + '/cfe/trunk', CLANG_DIR)
+  Checkout('LLD', LLVM_REPO_URL + '/lld/trunk', LLD_DIR)
   Checkout('compiler-rt', LLVM_REPO_URL + '/compiler-rt/trunk', COMPILER_RT_DIR)
 
   if not os.path.exists(LLVM_BUILD_DIR):
     os.makedirs(LLVM_BUILD_DIR)
   os.chdir(LLVM_BUILD_DIR)
 
   RunCommand(GetVSVersion().SetupScript('x64') +
              ['&&', 'cmake', '-GNinja', '-DCMAKE_BUILD_TYPE=Release',
               '-DLLVM_ENABLE_ASSERTIONS=ON', SubversionCmakeArg(), LLVM_DIR])
   RunCommand(GetVSVersion().SetupScript('x64') + ['&&', 'ninja', 'all'])
@@ skipping 67 matching lines @@
 
   if re.search(r'\b(make_clang_dir)=', os.environ.get('GYP_DEFINES', '')):
     print 'Skipping Clang update (make_clang_dir= was set in GYP_DEFINES).'
     return 0
 
   return UpdateClang()
 
 
 if __name__ == '__main__':
   sys.exit(main())