Add the URL file name to the uniqueId.
Add the URL file name to the uniqueId.

Needed to ensure that window.history.back() is correctly detected.  Previously, the newly-navigated-to test would run and pass and the test runner would accept it as a passed test.  By including the URL, the test runner can detect that the wrong test passed.

Clear the uniqueId on pagehide (cache or unload).

RELNOTES: n/a

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=182470939

lucidsoftware/closure-library,google/closure-library,lucidsoftware/closure-library,teppeis/closure-library,teppeis/closure-library,google/closure-library,google/closure-library,teppeis/closure-library,lucidsoftware/closure-library,lucidsoftware/closure-library,google/closure-library,teppeis/closure-library,google/closure-library