Merge 55474 - Fix chrome frame upgrade from old to new beta...

Merge 55474 - Fix chrome frame upgrade from old to new beta

During upgrade process, two versions of chrome frame may get
loaded in IE at the same time. We have a DLL redirection code
to avoid conflicts when this happens. However, we changed the
way this redirect code works after the first beta and hence
need to fix new code to make it work with older version to 
avoid a crash during upgrade.

BUG=51620
TEST=test upgrade from 5.0.375.125 to 6.0.472.XXX while IE is
running and try 'Open in New window' etc.. 


Review URL: http://codereview.chromium.org/3119001

TBR=amit@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=55475