Moves multiple classes into their own files. Renames several classes and
the associated test classes. Moves a few of those classes (files) into
the parent directory. Converts snippets to use constructor tear-offs
rather than static method tear-offs.
Change-Id: If1aae3cc468d20ef056e650c0206fcfbf3c94f62
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/253004
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Brian Wilkerson
b7edb69e97