[MD History] Close delete items dialog when a new query is initiated.

This CL fixes an issue where the dialog in MD History would stay open
when the user pressed the Back button in the browser. As a catchall, the
dialog will now close when any non-incremental query is initiated.

BUG=630584
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2186073003
Cr-Commit-Position: refs/heads/master@{#409472}
2 files changed