Updating the Chrome reference build to revision 51178. This revision will currently only be pulled in for ChromeFrame performance tests. TBR=chase,amit Review URL: http://codereview.chromium.org/2824040 git-svn-id: http://src.chromium.org/svn/trunk/deps/reference_builds/chrome@51194 4ff67af0-8c30-449e-8e8b-ad334ec8d88c