[Telemetry] Cache the InstallOnDevice method.

The page cyclers call this during each page iteration and it is expensive.

BUG=

Review URL: https://codereview.chromium.org/147783003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250425 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250425