Compiles js modules with dartdevc based on `.moduleConfig` files and the corresponding linked summaries from the `LinkedSummaryTransformer`.

Creates linked summaries for modules based on .moduleConfig files, using unlinked summaries from the previous step.

Closes #1567

* add ScratchSpace class which manages creating temp environments for running external binaries
* add analyzer worker driver and bazel_worker dependency
* add the UnlinkedSummaryTransformer
* rename modules after creation so the names arent so long
* Add UnlinkedSummaryTransformer to packages, use file: uris for analyzer cli

This transformer creates .moduleConfig files under each top level directory in a package, using the `computeModules` function.

Throws UnimplementedError if passing dartdevc today

* add `_ModuleComputer` class and top level `computeModules` function.
  * uses tarjans algorithm to create strongly connected components first
  * then groups modules based on the entry points that import them
* move InMemoryModuleConfigManager to util.dart
* add equalsModule as a proper matcher, and makeAssets test utility
* add isPart function to lib/src/dart.dart and add proper support for part files

Add Module/ModuleId/ModuleReader classes for storing/reading module config information

Fix #1560.

Fixes #1336

Record when we log and error and mark the entire build as failed. This
catches the cases where there are errors on assets that did not
transitively impact dart2js output - like transformers on non-Dart
files.

The current ignore is too broach and matches some of the tests. A
leading slash makes the ignore only match a build directory at the root
of the repo

Just like test and tool
Also expanded and generalized these tests

Closes https://github.com/dart-lang/pub/issues/1537

Fixes #1535

The tests execute `git` in a number of places which is impacted by the
users global git config and can cause failure.

- Remove `info` and `hooks` from the list of required directories under
  `.git`. These are controlled by the `init.templatedir` config and are
  only the defaults but may not exist.
- For git repos created during the test configure `core.excludesfile` as
  empty since we rely on having full control over ignored files when we
  create `.gitignore` ourself.

Use a home-rolled version

* Add metadata to requests to pub.dartlang.org.

This will help pub.dartlang.org better track how packages relate to one
another.

* Fix broken depenency tests.

Those unit tests import pub libraries directly without invoking a
command, so command was throwing an exception. Worse, the Pokemon
exception handler in DependencyValidator was then catching the
StateError, hiding the bug.

Also applied some other changes I suggested.

Get the Mac tests passing again with the mtree stuff in tar.

run dartfmt

Closes #1519

"git ls-files" doesn't recurse into submodules, so we need to do so
manually.

Closes #1523

Fixes #1442

I'm not sure why this wasn't causing us problems before.

Closes #1514

This adds a validator that warns when a package incorrectly imports a non-dependency.

R=nweiz@google.com, rnystrom@google.com

BUG= https://github.com/dart-lang/pub/issues/1511

Review-Url: https://codereview.chromium.org//2653753010 .

Fix two strong-mode warnings

Disable passing "--uname" and "--gname" to tar on non-Linux.

That hits OS X too, and the version of tar on OS X doesn't support
those. :(

Run executables in Isolates.