Show change password card on already opened chrome://settings page

If user has chrome://settings already opened in some tabs, and
encountered a password reuse warning, the change password setting
card should show on these already opened chrome://settings page
as soon as the password reuse modal warning is shown.

Other fixes include: (1) exit fullscreen when warning is shown;
(2) add js tests in 
chrome/test/data/webui/settings/change_password_page_test.js
(3) minor refactoring in PasswordProtectionService.

Bug: 765740,773537
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I4372b6448cc5a612a9866b1f94692eeb0cfd56e7
Reviewed-on: https://chromium-review.googlesource.com/753986
Reviewed-by: Demetrios Papadopoulos <[email protected]>
Reviewed-by: Raymes Khoury <[email protected]>
Reviewed-by: Nathan Parker <[email protected]>
Commit-Queue: Jialiu Lin <[email protected]>
Cr-Commit-Position: refs/heads/master@{#514530}
12 files changed