Separated SparkUiAccess into Ui and Dom classes (to remove possible circular references).  Added mousedown and mouseup to ClickElement handler to fix test case.  Separated onTransitionComplete handler from actual transition event.  Fixed 3 tests and removed disabling of a fourth one (so that it tests locally as we as headless).  Added flag to getProjectLocation so that we can forego the project dialog if no root has been selected.
Merge branch 'master' of https://github.com/dart-lang/chromedeveditor into umop-fix-ui_tests
Merge pull request #3657 from dart-lang/umop-fix-ui_tests

Fixed UI tests