Simplify PackageMapUriResolver - one folder, return any file, or null.

Simplify PackageMapUriResolver - one folder, return any file, or null.

If the package is know, we return the corresponding file, whether it
exists or not.

If the package is not know, there is no valid Source to resolve to,
so we return null.


We don't need all the features that existed.

Internally we switched to BazelPackageUriResolver, which has its own
logica for searching files in workspaces across multiple folders.

All the places where we create PackageMapUriResolver in analyzer
or analysis_server, we create it with exactly one folder.

R=brianwilkerson@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/6fe8e2278b2cb678ad016b6151c12d016bc7a7db

[Brian Wilkerson, 2017-04-11 20:00:13]

lgtm

[scheglov, 2017-04-11 20:04:03]

Description was changed from

==========
Simplify PackageMapUriResolver - one folder, return any file, or null.

If the package is know, we return the corresponding file, whether it
exists or not.

If the package is not know, there is no valid Source to resolve to,
so we return null.


We don't need all the features that existed.

Internally we switched to BazelPackageUriResolver, which has its own
logica for searching files in workspaces across multiple folders.

All the places where we create PackageMapUriResolver in analyzer
or analysis_server, we create it with exactly one folder.

R=brianwilkerson@google.com
BUG=
==========

to

==========
Simplify PackageMapUriResolver - one folder, return any file, or null.

If the package is know, we return the corresponding file, whether it
exists or not.

If the package is not know, there is no valid Source to resolve to,
so we return null.


We don't need all the features that existed.

Internally we switched to BazelPackageUriResolver, which has its own
logica for searching files in workspaces across multiple folders.

All the places where we create PackageMapUriResolver in analyzer
or analysis_server, we create it with exactly one folder.

R=brianwilkerson@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/6fe8e2278b2cb678ad016b6151c12d016bc7a7db
==========

[scheglov, 2017-04-11 20:04:04]

Committed patchset #1 (id:1) manually as
6fe8e2278b2cb678ad016b6151c12d016bc7a7db (presubmit successful).