Increased upper limit on renderer event latency UMA histogram.

BUG=329687

Review URL: https://codereview.chromium.org/138593003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246269 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246269