Mac: Fix close/min/zoom buttons highlighting on bookmark hover.
Mac: Fix close/min/zoom buttons highlighting on bookmark hover.

The default mouseEntered: implementation forwards to the next responder, and this ends up being the window. Cells don't usually forward this to their view (views only get this if they install tracking areas). So don't forward this to super.

TEST=mouse over a bookmark. Close button shouldn't highlight.
BUG=36814

Review URL: http://codereview.chromium.org/998003

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@41648 0039d316-1c4b-4281-b951-d872f2087c98

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