Navigate to "about:blank" before calling GC so that the current page does not hold references to DOM objects.
Navigate to "about:blank" before calling GC so that the current
page does not hold references to DOM objects.

This should reduce noise of reporting leaked nodes.

Review URL: http://codereview.chromium.org/12936

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@6377 0039d316-1c4b-4281-b951-d872f2087c98

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