[infra] Roll clang to match the version used by Flutter

tools/android/download_android_tools.py

Index: tools/android/download_android_tools.py
diff --git a/tools/android/download_android_tools.py b/tools/android/download_android_tools.py
new file mode 100644
index 0000000000000000000000000000000000000000..e16989f3146abdad5c3d3af321ca335b37c143c8
--- /dev/null
+++ b/tools/android/download_android_tools.py
@@ -0,0 +1,104 @@
+#!/usr/bin/env python
+# Copyright 2017 The Dart project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Downloads trimmed-down Android Tools from Google Cloud Storage and extracts
+# them to INSTALL_DIR, updating INSTALL_DIR/VERSION_* stamp files with current
+# version. Does nothing if INSTALL_DIR/VERSION_* are already up to date.
+
+import os
+import shutil
+import subprocess
+import sys
+import tarfile
+
+# Path constants. (All of these should be absolute paths.)
+THIS_DIR = os.path.abspath(os.path.dirname(__file__))
+DART_ROOT = os.path.abspath(os.path.join(THIS_DIR, '..', '..'))
+# Should be the same as in upload.py.
+INSTALL_DIR = os.path.join(DART_ROOT, 'third_party', 'android_tools')
+
+sys.path.insert(0, os.path.join(DART_ROOT, 'tools'))
+import find_depot_tools
+
+DEPOT_PATH = find_depot_tools.add_depot_tools_to_path()
+GSUTIL_PATH = os.path.join(DEPOT_PATH, 'gsutil.py')
+
+def RunCommand(command):
+  """Run command and return success (True) or failure."""
+
+  print 'Running %s' % (str(command))
+  if subprocess.call(command, shell=False) == 0:
+    return True
+  print 'Failed.'
+  return False
+
+
+def GetInstalledVersion(version_stamp):
+  version_file = os.path.join(INSTALL_DIR, version_stamp)
+  if not os.path.exists(version_file):
+    return None
+  with open(version_file) as f:
+    return f.read().strip()
+
+
+def VersionStampName(tools_name):
+  if sys.platform.startswith('linux'):
+    return 'VERSION_LINUX_' + tools_name.upper()
+  elif sys.platform == 'darwin':
+    return 'VERSION_MACOSX_' + tools_name.upper()
+  else:
+    print('NOTE: Will not download android tools. Unsupported platform: ' + sys.platform)
+    sys.exit(0)
+
+
+def UpdateTools(tools_name):
+  """Downloads zipped tools from Google Cloud Storage and extracts them,
+     stamping current version."""
+
+  # Read latest version.
+  version_stamp = VersionStampName(tools_name)
+  version = ''
+  with open(os.path.join(THIS_DIR, version_stamp)) as f:
+    version = f.read().strip()
+  # Return if installed binaries are up to date.
+  if version == GetInstalledVersion(version_stamp):
+    return
+
+  # Remove the old install directory checked out from git.
+  if os.path.exists(os.path.join(INSTALL_DIR, '.git')):
+    shutil.rmtree(INSTALL_DIR)
+  # Make sure that the install directory exists.
+  if not os.path.exists(INSTALL_DIR):
+    os.mkdir(INSTALL_DIR)
+  # Remove current installation.
+  tools_root = os.path.join(INSTALL_DIR, tools_name)
+  if os.path.exists(tools_root):
+    shutil.rmtree(tools_root)
+
+  # Download tools from GCS.
+  archive_path = os.path.join(INSTALL_DIR, tools_name + '.tar.gz')
+  download_cmd = ['python', GSUTIL_PATH, 'cp',
+                  'gs://mojo/android/tool/%s.tar.gz' % version,
+                  archive_path]
+  if not RunCommand(download_cmd):
+    print ('WARNING: Failed to download Android tools.')
+    return
+
+  print "Extracting Android tools (" + tools_name + ")"
+  with tarfile.open(archive_path) as arch:
+    arch.extractall(INSTALL_DIR)
+  os.remove(archive_path)
+  # Write version as the last step.
+  with open(os.path.join(INSTALL_DIR, version_stamp), 'w+') as f:
+    f.write('%s\n' % version)
+
+
+def main():
+  UpdateTools('sdk')
+  UpdateTools('ndk')
+
+
+if __name__ == '__main__':
+  sys.exit(main())