Implements basic listing of USB drives for windows.

BUG=310328

Review URL: https://codereview.chromium.org/30593007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247892 0039d316-1c4b-4281-b951-d872f2087c98
Add a Settings.FilterOnLoadTime histogram to observe time spent on this critical path in the wild.

This call is on the startup path; we believe all regressions have been addressed, but would like data from the wild to see how this truly behaves in various user configurations.

BUG=330908

Review URL: https://codereview.chromium.org/149073003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247893 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247892
SVN changes up to revision 247893