A couple of weeks ago angry birds -web- got a new version that is capable of working offline with HTML5 Cache !
Today, I tried to delete the cache and re-install the game .. and it worked fine =)
Here is HOW:
Options >under the Hood > Content settings > Click “All Cookies and site data…”
OR simply write chrome://settings/cookies in your address bar !
You will find a long list of all sites “Cookies and Other Data” in your browser !
in the small box above write “chrome.angrybirds”
You will find only 1 entry filter, click “session storage” then > “Remove”
NOTE: All your saved data <levels> will be lost ! (90%)
Now.. open up your angry birds web app and wait for the installation.
and u r done =D