Reduce the amount of excessive updating done when there is no window icon to be updated.
Reduce the amount of excessive updating done when there is no window icon to be
updated.

Improves sunspider results.


git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@2879 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,yitian134/chromium,ropik/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,gavinp/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,ropik/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,ropik/chromium,yitian134/chromium,adobe/chromium