
Dispose of event listener. This isn't really a performance improvement but it reduces the noise in the tests a lot.

R=pupius
DELTA=17  (16 added, 0 deleted, 1 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=266


yamadatomonori/closure-library,yamadatomonori/closure-library,yamadatomonori/closure-library