Update Dart SDK to 1.12.0-dev.3.1

tools/dart/update.py

 #!/usr/bin/python
 # Copyright 2015 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.
 
 """Pulls down the current dart sdk to third_party/dart-sdk/.
 
 You can manually force this to run again by removing
 third_party/dart-sdk/STAMP_FILE, which contains the URL of the SDK that
 was downloaded. Rolling works by updating LINUX_64_SDK to a new URL.
 """
 
 import os
 import shutil
 import subprocess
 import sys
 
 # How to roll the dart sdk: Just change this url! We write this to the stamp
 # file after we download, and then check the stamp file for differences.
-SDK_URL_BASE = ('http://gsdview.appspot.com/dart-archive/channels/dev/'
-                'raw/45311/sdk/')
+SDK_URL_BASE = ('http://gsdview.appspot.com/dart-archive/channels/dev/raw/'
+                '1.12.0-dev.3.1/sdk/')
 
 LINUX_64_SDK = 'dartsdk-linux-x64-release.zip'
 MACOS_64_SDK = 'dartsdk-macos-x64-release.zip'
 
 # Path constants. (All of these should be absolute paths.)
 THIS_DIR = os.path.abspath(os.path.dirname(__file__))
 MOJO_DIR = os.path.abspath(os.path.join(THIS_DIR, '..', '..'))
 DART_SDK_DIR = os.path.join(MOJO_DIR, 'third_party', 'dart-sdk')
 STAMP_FILE = os.path.join(DART_SDK_DIR, 'STAMP_FILE')
 LIBRARIES_FILE = os.path.join(DART_SDK_DIR,'dart-sdk',
@@ skipping 56 matching lines @@
 
     # Write our stamp file so we don't redownload the sdk.
     with open(STAMP_FILE, "w") as stamp_file:
       stamp_file.write(sdk_url)
 
   unzip_command = ['unzip', '-o', '-q', output_file, '-d', DART_SDK_DIR]
   if not RunCommand(unzip_command, fail_hard=False):
     print "Failed to unzip the dart sdk."
     return 1
 
-  # Patch the the dart-sdk/lib/_internal/libraries.dart file
-  # so that it understands dart:sky imports.
-  patch_command = ['patch', LIBRARIES_FILE, PATCH_FILE]
-  if not RunCommand(patch_command, fail_hard=False):
-    print "Failed to apply the patch to the Dart libraries file."
-    return 1
   return 0
 
 if __name__ == '__main__':
   sys.exit(main())