diff --git a/pkgs/clock/.gitignore b/pkgs/clock/.gitignore
new file mode 100644
index 0000000..63fe85d
--- /dev/null
+++ b/pkgs/clock/.gitignore
@@ -0,0 +1,5 @@
+.packages
+.pub/
+.dart_tool/
+build/
+pubspec.lock
diff --git a/pkgs/clock/.travis.yml b/pkgs/clock/.travis.yml
new file mode 100644
index 0000000..9124e03
--- /dev/null
+++ b/pkgs/clock/.travis.yml
@@ -0,0 +1,33 @@
+language: dart
+
+# By default, builds are run in containers.
+# https://docs.travis-ci.com/user/getting-started/#Selecting-infrastructure-(optional)
+# Set `sudo: true` to disable containers if you need to use sudo in your scripts.
+# sudo: true
+
+dart:
+- dev
+- stable
+
+# See https://docs.travis-ci.com/user/languages/dart/ for details.
+dart_task:
+- test: --platform vm
+# Uncomment this line to run tests on the browser.
+# - test: --platform firefox
+
+# Only run one instance of the formatter and the analyzer, rather than running
+# them against each Dart version.
+matrix:
+  include:
+  - dart: stable
+    dart_task: dartfmt
+  - dart: dev
+    dart_task: dartanalyzer
+
+# Only building master means that we don't run two builds for each pull request.
+branches:
+  only: [master]
+
+cache:
+  directories:
+  - $HOME/.pub-cache
diff --git a/pkgs/clock/AUTHORS b/pkgs/clock/AUTHORS
new file mode 100644
index 0000000..e8063a8
--- /dev/null
+++ b/pkgs/clock/AUTHORS
@@ -0,0 +1,6 @@
+# Below is a list of people and organizations that have contributed
+# to the project. Names should be added to the list like so:
+#
+#   Name/Organization <email address>
+
+Google Inc.
diff --git a/pkgs/clock/CHANGELOG.md b/pkgs/clock/CHANGELOG.md
new file mode 100644
index 0000000..5b26ad3
--- /dev/null
+++ b/pkgs/clock/CHANGELOG.md
@@ -0,0 +1,3 @@
+## 1.0.0
+
+* Initial version.
diff --git a/pkgs/clock/CONTRIBUTING.md b/pkgs/clock/CONTRIBUTING.md
new file mode 100644
index 0000000..615b92f
--- /dev/null
+++ b/pkgs/clock/CONTRIBUTING.md
@@ -0,0 +1,53 @@
+Want to contribute? Great! First, read this page (including the small print at
+the end).
+
+### Before you contribute
+
+Before we can use your code, you must sign the
+[Google Individual Contributor License Agreement][CLA] (CLA), which you can do
+online. The CLA is necessary mainly because you own the copyright to your
+changes, even after your contribution becomes part of our codebase, so we need
+your permission to use and distribute your code. We also need to be sure of
+various other things—for instance that you'll tell us if you know that your code
+infringes on other people's patents. You don't have to sign the CLA until after
+you've submitted your code for review and a member has approved it, but you must
+do it before we can put your code into our codebase.
+
+Before you start working on a larger contribution, you should get in touch with
+us first through the issue tracker with your idea so that we can help out and
+possibly guide you. Coordinating up front makes it much easier to avoid
+frustration later on.
+
+[CLA]: https://cla.developers.google.com/about/google-individual
+
+### Code reviews
+
+All submissions, including submissions by project members, require review. We
+recommend [forking the repository][fork], making changes in your fork, and
+[sending us a pull request][pr] so we can review the changes and merge them into
+this repository.
+
+[fork]: https://help.github.com/articles/about-forks/
+[pr]: https://help.github.com/articles/creating-a-pull-request/
+
+Functional changes will require tests to be added or changed. The tests live in
+the `test/` directory, and are run with `pub run test`. If you need to create
+new tests, use the existing tests as a guideline for what they should look like.
+
+Before you send your pull request, make sure all the tests pass!
+
+### File headers
+
+All files in the project must start with the following header.
+
+    // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+    // for details. All rights reserved. Use of this source code is governed by a
+    // BSD-style license that can be found in the LICENSE file.
+
+### The small print
+
+Contributions made by corporations are covered by a different agreement than the
+one above, the
+[Software Grant and Corporate Contributor License Agreement][CCLA].
+
+[CCLA]: https://developers.google.com/open-source/cla/corporate
diff --git a/pkgs/clock/LICENSE b/pkgs/clock/LICENSE
new file mode 100644
index 0000000..7a4a3ea
--- /dev/null
+++ b/pkgs/clock/LICENSE
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
\ No newline at end of file
diff --git a/pkgs/clock/README.md b/pkgs/clock/README.md
new file mode 100644
index 0000000..905f3b3
--- /dev/null
+++ b/pkgs/clock/README.md
@@ -0,0 +1,48 @@
+This package provides a [`Clock`][] class which encapsulates the notion of the
+"current time" and provides easy access to points relative to the current time.
+Different `Clock`s can have a different notion of the current time, and the
+default top-level [`clock`][]'s notion can be swapped out to reliably test
+timing-dependent code.
+
+[`Clock`]: https://www.dartdocs.org/documentation/clock/latest/clock/Clock-class.html
+[`clock`]: https://www.dartdocs.org/documentation/clock/latest/clock/clock.html
+
+For example, you can use `clock` in your libraries like this:
+
+```dart
+// run_with_timing.dart
+import 'package:clock/clock.dart';
+
+/// Runs [callback] and prints how long it took.
+T runWithTiming<T>(T callback()) {
+  var stopwatch = clock.getStopwatch()..start();
+  var result = callback();
+  print("It took ${stopwatch.elapsed}!");
+  return result;
+}
+```
+
+...and then test your code using the [`fake_async`][] package, which
+automatically overrides the current clock:
+
+[`fake_async`]: https://pub.dartlang.org/packages/fake_async
+
+```dart
+// run_with_timing_test.dart
+import 'run_with_timing.dart';
+
+import 'package:fake_async/fake_async.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test("runWithTiming() prints the elapsed time", () {
+    new FakeAsync().run((async) {
+      expect(() {
+        runWithTiming(() {
+          async.elapse(new Duration(seconds: 10));
+        });
+      }, prints("It took 0:00:10.000000!"));
+    });
+  });
+}
+```
diff --git a/pkgs/clock/analysis_options.yaml b/pkgs/clock/analysis_options.yaml
new file mode 100644
index 0000000..a10d4c5
--- /dev/null
+++ b/pkgs/clock/analysis_options.yaml
@@ -0,0 +1,2 @@
+analyzer:
+  strong-mode: true
diff --git a/pkgs/clock/pubspec.yaml b/pkgs/clock/pubspec.yaml
new file mode 100644
index 0000000..52d25d2
--- /dev/null
+++ b/pkgs/clock/pubspec.yaml
@@ -0,0 +1,8 @@
+name: clock
+version: 1.0.0-dev
+description: A fakeable wrapper for dart:core clock APIs
+author: Dart Team <misc@dartlang.org>
+homepage: https://github.com/dart-lang/clock
+
+environment:
+  sdk: '>=1.24.0 <2.0.0'