Its a wrong opinion that Mozilla is surviving because of Google. Did google invest on Mozilla to start the project?

Mozilla Firefox is a opensource project. Now Google has extended its agreement just to get the benefits from the Frirefox and it is also a strategic move. This three year agreement is just a strategic move taken and timelline given by Google to vanish the name of Firefox from the Browser market.

Chrome can replace the Firefox, but it cannot become as Firefox.

Today most of the searches are made by the Firefox users through the Firefox search bar and hence Google has made a tieup with Mozilla. Let us see what happens after three years.