Use the correct preload field trial name in page_load_histograms.cc.
Use the correct preload field trial name in page_load_histograms.cc.

BUG=75682
TEST=none

Review URL: http://codereview.chromium.org/6646056

git-svn-id: http://src.chromium.org/svn/trunk/src@78055 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 24398aa44bdb098a802f57d9f48e626d4c8cc63b
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser