Add an empty about:password-manager-internals page.

Adds a page at chrome://password-manager-internals, showing currently uninteresting static content. This is hidden behind a command-line flag.

This is the first step of the design outlined in https://docs.google.com/document/d/1ArDhTo0w-8tOPiTwqM1gG6ZGqODo8UTpXlJjjnCNK4s/edit?usp=sharing

Further steps will add also some functionality for updating the page with interesting data. :)

BUG=347927

Review URL: https://codereview.chromium.org/184413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254299 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254299
adds support for Win8-style app protocols

Some protocol URLs on Windows 8, such as xboxgames://, rely on Chrome
calling AssocQueryString to discover the associated application
instead of scraping the registry as we have done in the past. Modifies
the code to do so, if we are on Windows 8 or above.

BUG=159096
Test=None
TBR=thakis

Review URL: https://codereview.chromium.org/173093003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254300 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254300