Fix the SSL interstitial UMA stats

Just discovered that I broke the UMA stats during one of my recent refactorings. Here's what went wrong:

The interstitial is supposed to send a FOCUS event to indicate that page load timing should start. RecordSSLBlockingPageDetailedStats only records UMA stats if the page has a non-null page load time. At some point, I deleted the code that sent the FOCUS event, so the page load time was always null.

We don't need any of the timing stuff anymore, so I've gotten rid of all of it. This also fixes the bug.

BUG=314416

Review URL: https://codereview.chromium.org/57183002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232809 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232809