[Telemetry] Move WillRunPageSet call to a point where browser.http_server exists
[Telemetry] Move WillRunPageSet call to a point where browser.http_server exists

The page cycler's implementation of WillRunPageSet will access http_server.UrlOf
so http_server needs to be defined. This moves the call to a point after
SetHTTPServerDirectories has been called.

BUG=None
TEST=None
NOTRY=True


Review URL: https://chromiumcodereview.appspot.com/13972004

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@193531 0039d316-1c4b-4281-b951-d872f2087c98

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