Fix Password Manager Performance Issues

This change further addresses the performance issue of password manager when
many passwords are saved. Prior to this change a long password list (~1000
entries) can freeze the password manager for multiple seconds.

Inspired by the edit dictionary settings (chrome://settings/editDictionary),
this change removes the |autoExpands| attributes from the saved passwords and
password exceptions lists and adds a CSS |max-height| attribute. This results in
rendering the list almost instantaneously and keeps it responsive with regard to
user interactions.

BUG=651049
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2443143002
Cr-Commit-Position: refs/heads/master@{#427655}
2 files changed