Remove vendored dart-sdk (#2688)

The engine.git repo doesn't need a copy of the Dart SDK anymore.

Fixes https://github.com/flutter/flutter/issues/2618
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 0664f85..be17b19 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -46,7 +46,6 @@
  * `cd src` (Change to the directory that `gclient sync` created in your `engine` directory.)
  * `git remote add upstream git@github.com:flutter/engine.git` (So that you fetch from the master repository, not your clone, when running `git fetch` et al.)
  * Run `./tools/android/download_android_tools.py` to add Android dependencies to your tree. You will need to run this command again if you ever run `git clean -xdf`, since that deletes these dependencies. (`git clean -df` is fine since it skips these `.gitignore`d files.)
- * Add `.../engine/src/third_party/dart-sdk/dart-sdk/bin/` to your path so that you can run the `pub` tool more easily.
  * Add `.../engine/src/third_party/android_tools/sdk/platform-tools` to your path so that you can run the `adb` tool more easily. This is also required by the `flutter` tool, which is used to run Flutter apps.
  * Make sure you are still in the `src` directory that the `gclient sync` step created earlier.
  * If you're on Linux, run `sudo ./build/install-build-deps-android.sh`
diff --git a/DEPS b/DEPS
index 1027ac2..52fb08a 100644
--- a/DEPS
+++ b/DEPS
@@ -134,12 +134,6 @@
     'action': ['python', 'src/tools/clang/scripts/update.py', '--if-needed'],
   },
   {
-    # Pull dart sdk if needed
-    'name': 'dart',
-    'pattern': '.',
-    'action': ['python', 'src/tools/dart/update.py'],
-  },
-  {
     # Update LASTCHANGE. This is also run by export_tarball.py in
     # src/tools/export_tarball - please keep them in sync.
     'name': 'lastchange',
diff --git a/sky/tools/release_engine.py b/sky/tools/release_engine.py
deleted file mode 100755
index d9dc824..0000000
--- a/sky/tools/release_engine.py
+++ /dev/null
@@ -1,187 +0,0 @@
-#!/usr/bin/env 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.
-
-# See https://github.com/domokit/sky_engine/wiki/Release-process
-
-import argparse
-import os
-import subprocess
-import sys
-import distutils.util
-import tempfile
-import zipfile
-
-
-DRY_RUN = False
-
-
-def run(cwd, args):
-    print 'RUNNING:', ' '.join(args), 'IN:', cwd
-    if DRY_RUN:
-        return
-    subprocess.check_call(args, cwd=cwd)
-
-
-def confirm(prompt):
-    user_input = raw_input("%s (y/N) " % prompt)
-    try:
-        return distutils.util.strtobool(user_input) == 1
-    except ValueError:
-        return False
-
-
-def git_revision(cwd):
-    return subprocess.check_output([
-        'git', 'rev-parse', 'HEAD',
-    ], cwd=cwd).strip()
-
-
-GS_URL = 'gs://mojo/flutter/%(commit_hash)s/%(config)s/%(name)s'
-
-
-# Paths of the artifacts that will be packaged into a zip file.
-ZIP_ARTIFACTS = {
-    'android-arm': [
-        'chromium-debug.keystore',
-        'icudtl.dat',
-        'dist/shell/SkyShell.apk',
-        'dist/shell/flutter.mojo',
-        'gen/sky/shell/shell/classes.dex.jar',
-        'gen/sky/shell/shell/shell/libs/armeabi-v7a/libsky_shell.so',
-        # TODO(mpcomplete): obsolete. Remove after updating the flutter tool.
-        'gen/sky/shell/shell/classes.dex',
-    ],
-    'linux-x64': [
-        'dist/shell/icudtl.dat',
-        'dist/shell/sky_shell',
-        'dist/shell/sky_snapshot',
-        'dist/shell/flutter.mojo',
-    ],
-}
-
-
-# Paths of the artifacts that will be uploaded to GCS as individual files.
-FILE_ARTIFACTS = {
-    'android-arm': [
-        'dist/shell/flutter.mojo',
-        'dist/shell/libflutter_library.so',
-    ],
-    'linux-x64': [
-        'dist/shell/flutter.mojo',
-        'dist/shell/libflutter_library.so',
-    ],
-}
-
-
-def find_missing_artifacts(config, config_root):
-    result = []
-    for artifact_map in [ZIP_ARTIFACTS, FILE_ARTIFACTS]:
-        for artifact_path in artifact_map[config]:
-            full_path = os.path.join(config_root, artifact_path)
-            if not os.path.exists(full_path):
-                result.append(full_path)
-    return result
-
-
-# Do not try to compress file types that are already compressed.
-FILE_TYPE_COMPRESSION = {
-    '.apk': zipfile.ZIP_STORED,
-}
-
-
-def upload_artifacts(dist_root, config, commit_hash):
-    # Build and upload a zip file of artifacts
-    zip_fd, zip_filename = tempfile.mkstemp('.zip', 'artifacts_')
-    try:
-        os.close(zip_fd)
-        artifact_zip = zipfile.ZipFile(zip_filename, 'w')
-        for artifact_path in ZIP_ARTIFACTS[config]:
-            _, extension = os.path.splitext(artifact_path)
-            artifact_zip.write(os.path.join(dist_root, artifact_path),
-                               os.path.basename(artifact_path),
-                               FILE_TYPE_COMPRESSION.get(extension, zipfile.ZIP_DEFLATED))
-        artifact_zip.close()
-        dst = GS_URL % {
-            'config': config,
-            'commit_hash': commit_hash,
-            'name': 'artifacts.zip',
-        }
-        run(dist_root, ['gsutil', 'cp', zip_filename, dst])
-    finally:
-        os.remove(zip_filename)
-
-    # Upload individual file artifacts
-    for artifact_path in FILE_ARTIFACTS[config]:
-        dst = GS_URL % {
-            'config': config,
-            'commit_hash': commit_hash,
-            'name': os.path.basename(artifact_path),
-        }
-        z = ','.join([ 'mojo', 'so' ])
-        run(dist_root, ['gsutil', 'cp', '-z', z, artifact_path, dst])
-
-
-def main():
-    parser = argparse.ArgumentParser(description='Deploy!')
-    parser.add_argument('--dry-run', action='store_true', default=False,
-        help='Just print commands w/o executing.')
-    parser.add_argument('--revision', help='The git revision to publish.')
-    args = parser.parse_args()
-
-    global DRY_RUN
-    DRY_RUN = args.dry_run
-
-    engine_root = os.path.abspath('.')
-    if not os.path.exists(os.path.join(engine_root, 'sky')):
-        print "Cannot find //sky. Is %s the Flutter engine repository?" % engine_root
-        return 1
-
-    commit_hash = git_revision(engine_root)
-
-    if commit_hash != args.revision:
-        print "Current revision %s does not match requested revision %s." % (commit_hash, args.revision)
-        print "Please update the current revision to %s." % args.revision
-        return 1
-
-    # Derived paths:
-    dart_sdk_root = os.path.join(engine_root, 'third_party/dart-sdk/dart-sdk')
-    pub_path = os.path.join(dart_sdk_root, 'bin/pub')
-    android_out_root = os.path.join(engine_root, 'out/android_Release')
-    linux_out_root = os.path.join(engine_root, 'out/Release')
-    sky_engine_package_root = os.path.join(android_out_root, 'dist/packages/sky_engine/sky_engine')
-    sky_services_package_root = os.path.join(android_out_root, 'dist/packages/sky_services/sky_services')
-    sky_engine_revision_file = os.path.join(sky_engine_package_root, 'lib', 'REVISION')
-
-    run(engine_root, ['sky/tools/gn', '--android', '--release'])
-    run(engine_root, ['ninja', '-C', 'out/android_Release', ':dist'])
-
-    run(engine_root, ['sky/tools/gn', '--release'])
-    run(engine_root, ['ninja', '-C', 'out/Release', ':dist'])
-
-    with open(sky_engine_revision_file, 'w') as stream:
-        stream.write(commit_hash)
-
-    configs = [('android-arm', android_out_root),
-               ('linux-x64', linux_out_root)]
-
-    # Check for missing artifact files
-    missing_artifacts = []
-    for config, config_root in configs:
-        missing_artifacts.extend(find_missing_artifacts(config, config_root))
-    if missing_artifacts:
-        print ('Build is missing files:\n%s' %
-               '\n'.join('\t%s' % path for path in missing_artifacts))
-        return 1
-
-    # Upload artifacts
-    for config, config_root in configs:
-        upload_artifacts(config_root, config, commit_hash)
-
-    run(sky_engine_package_root, [pub_path, 'publish', '--force'])
-    run(sky_services_package_root, [pub_path, 'publish', '--force'])
-
-
-if __name__ == '__main__':
-    sys.exit(main())
diff --git a/tools/dart/update.py b/tools/dart/update.py
deleted file mode 100755
index 41532ab..0000000
--- a/tools/dart/update.py
+++ /dev/null
@@ -1,101 +0,0 @@
-#!/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/stable/raw/'
-                '1.14.1/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',
-                              'lib', '_internal', 'libraries.dart')
-PATCH_FILE = os.path.join(MOJO_DIR, 'tools', 'dart', 'patch_sdk.diff')
-
-def RunCommand(command, fail_hard=True):
-  """Run command and return success (True) or failure; or if fail_hard is
-     True, exit on failure."""
-
-  print 'Running %s' % (str(command))
-  if subprocess.call(command, shell=False) == 0:
-    return True
-  print 'Failed.'
-  if fail_hard:
-    sys.exit(1)
-  return False
-
-def main():
-  # Only get the SDK if we don't have a stamp for or have an out of date stamp
-  # file.
-  get_sdk = False
-  if sys.platform.startswith('linux'):
-    sdk_url = SDK_URL_BASE + LINUX_64_SDK
-    output_file = os.path.join(DART_SDK_DIR, LINUX_64_SDK)
-  elif sys.platform.startswith('darwin'):
-    sdk_url = SDK_URL_BASE + MACOS_64_SDK
-    output_file = os.path.join(DART_SDK_DIR, MACOS_64_SDK)
-  else:
-    print "Platform not supported"
-    return 1
-
-  if not os.path.exists(STAMP_FILE):
-    get_sdk = True
-  else:
-    # Get the contents of the stamp file.
-    with open(STAMP_FILE, "r") as stamp_file:
-      stamp_url = stamp_file.read().replace('\n', '')
-      if stamp_url != sdk_url:
-        get_sdk = True
-
-  if get_sdk:
-    # Completely remove all traces of the previous SDK.
-    if os.path.exists(DART_SDK_DIR):
-      shutil.rmtree(DART_SDK_DIR)
-    os.mkdir(DART_SDK_DIR)
-
-    # Download the Linux x64 based Dart SDK.
-    # '-C -': Resume transfer if possible.
-    # '--location': Follow Location: redirects.
-    # '-o': Output file.
-    curl_command = ['curl',
-                    '-C', '-',
-                    '--location',
-                    '-o', output_file,
-                    sdk_url]
-    if not RunCommand(curl_command, fail_hard=False):
-      print "Failed to get dart sdk from server."
-      return 1
-
-    # 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
-
-  return 0
-
-if __name__ == '__main__':
-  sys.exit(main())