pub transformer does not get access to pubspec.yaml as an asset

[DartBot]

This issue was originally filed by @paulevans

---

What steps will reproduce the problem?

1. Write a transformer that attempts to use information in pubspec.yaml

What is the expected output? What do you see instead?
pubspec.yaml appears as asset
Actual:
pubspec.yaml never processed as asset

What version of the product are you using?
1.7.2

On what operating system?
Mac OS X

Please provide any additional information below.
Some metadata provided in the pubspec.yaml file (e.g. version. name, description) would be useful to some pub transformers

Work around:
On transformer construction current working directory is project root - so path can be constructed to pubspec.yaml at that point and read.

[DartBot]

This comment was originally written by @zoechi

---

Similar to http://dartbug.com/21020

[kasperl]

Added Area-Pub, Triaged labels.

[nex3]

Added Duplicate label.
Marked as being merged into #19434.

[DartBot]

This issue has been moved to dart-lang/pub#1191.