Add an Android fragment support library to third_party

DEPS

@@ -408,6 +408,14 @@ hooks = [
         'src/tools/android/download_android_tools.py',
     ],
   },
+  {
+    'name': 'download_android_support',
+    'pattern': '.',
+    'action': [
+        'python',
+        'src/flutter/tools/android_support/download_android_support.py',
+    ],
+  },
   {
     'name': 'buildtools',
     'pattern': '.',

tools/android_support/VERSION_SUPPORT_V13

@@ -0,0 +1 @@
+https://maven.google.com/com/android/support/support-fragment/28.0.0/support-fragment-28.0.0.aar

tools/android_support/download_android_support.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+# Copyright 2018 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.
+
+import os
+import sys
+import urllib2
+import cStringIO
+import zipfile
+
+# Path constants. (All of these should be absolute paths.)
+THIS_DIR = os.path.abspath(os.path.dirname(__file__))
+FLUTTER_DIR = os.path.abspath(os.path.join(THIS_DIR, '..', '..', '..'))
+INSTALL_DIR = os.path.join(FLUTTER_DIR, 'third_party', 'android_support')
+
+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 main():
+  # Read latest version.
+  version_stamp = 'VERSION_SUPPORT_V13'
+  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
+
+  # Download the AAR and extract the JAR.
+  aar = urllib2.urlopen(version).read()
+  aar_zip = zipfile.ZipFile(cStringIO.StringIO(aar))
+  if not os.path.exists(INSTALL_DIR):
+    os.mkdir(INSTALL_DIR)
+  with open(os.path.join(INSTALL_DIR, 'android_support_v13.jar'), 'w') as f:
+    f.write(aar_zip.read('classes.jar'))
+
+  # Write version as the last step.
+  with open(os.path.join(INSTALL_DIR, version_stamp), 'w') as f:
+    f.write('%s\n' % version)
+
+if __name__ == '__main__':
+  sys.exit(main())

tools/licenses/lib/main.dart

@@ -1938,6 +1938,7 @@ class RepositoryRootThirdPartyDirectory extends RepositoryGenericThirdPartyDirec
         && entry.name != 'binutils' // build-time dependency only
         && entry.name != 'instrumented_libraries' // unused according to chinmay
         && entry.name != 'android_tools' // excluded on advice
+        && entry.name != 'android_support' // build-time only
         && entry.name != 'googletest' // only used by tests
         && entry.name != 'skia' // treated as a separate component
         && super.shouldRecurse(entry);