This switches pub's tests over to using the stream matchers built into
test, as well as the test_descriptor, test_process, and
shelf_test_handler packages. It uses async/await rather than
scheduled_test's task queue.

This removes a layer of indirection which should make it much easier to
work on pub's test infrastructure, especially for people unfamiliar with
scheduled_test.

The actual change itself is tiny. However, almost all of pub's existing
integration tests validated the correct output by looking at the
contents of the generated "packages" dirs. :(

I fixed most of those to instead validate against the .packages file.

I didn't change the Git ones because the .packages files end up
containing paths that point to specific Git commits. Getting that
working felt like more work than it was worth right now.

When we fully remove support for packages directories, we'll want to
fix that.

Fix #1450.

R=nweiz@google.com

Review URL: https://codereview.chromium.org//2377063002 .

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1585513002 .

This folds the distinction between "resolved" and "unresolved"
descriptions into the distinction between PackageIds and PackageRefs. In
other words, all PackageIds now have resolved descriptions and all
PackageRefs now have unresolved descriptions. This makes it easier to
track which descriptions are resolved and express resolution constraints
via the type system.

This also restricts the creation of PackageRefs and PackageIds to source
classes, which helps ensure that the description format—which is an
implementation detail—doesn't leak into surrounding code.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1528523003 .

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1215833002.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1153643002

R=rnystrom@google.com
BUG=20947

Review URL: https://codereview.chromium.org//831983005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42936 260f80e4-7a28-3924-810f-c04153c831b5

Previously, the binaries were only updated if the version number had
changed. Now they're updated if just the commit changes. This also
improves the output of "pub upgrade" if a git dependency changes its
commit but not its version number.

R=rnystrom@google.com
BUG=21971

Review URL: https://codereview.chromium.org//844263004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42883 260f80e4-7a28-3924-810f-c04153c831b5

This uses the source spans exposed by the yaml package to associate pubspec
errors visually with the section of the pubspec that caused them.

R=rnystrom@google.com
BUG=14999

Review URL: https://codereview.chromium.org//351703004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37675 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=17854
RELNOTE=Don't fetch git repository unnecessarily when running "pub get".

Review URL: https://codereview.chromium.org//221383002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@34626 260f80e4-7a28-3924-810f-c04153c831b5

Previously, if a git dependency's version was locked but its repo
wasn't available locally, attempting to download it would crash pub.

This also enhances some logging infrastructure around git and other
processes.

R=alanknight@google.com
BUG=16470

Review URL: https://codereview.chromium.org//145633008

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@32264 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=7351
R=nweiz@google.com

Review URL: https://codereview.chromium.org//26284002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@28330 260f80e4-7a28-3924-810f-c04153c831b5