Fix for ExtensionApiTest.Popup flakiness
Fix for ExtensionApiTest.Popup flakiness

This fires the OnPopupClosed event in a later event via PostTask. This gives the popup time to complete closing before the OnPopupClosed is received by the extension

BUG=NONE
TEST=NONE

Review URL: http://codereview.chromium.org/1041004

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@41888 0039d316-1c4b-4281-b951-d872f2087c98

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