Fixed Task Manager FPS so that it shows 0 instead of 60 for background pages. 
Fixed Task Manager FPS so that it shows 0 instead of 60 for background pages. 


BUG=73206
TEST=manually


Review URL: http://codereview.chromium.org/8616004

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@111234 0039d316-1c4b-4281-b951-d872f2087c98

adobe/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,ropik/chromium,ropik/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,ropik/chromium,adobe/chromium,gavinp/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium