Using your phone to view the eclipse might not create a face melting situation like the bad guy from Raiders of the Lost Ark, but it will burn your corneas according to science people.

NASA says that yes you can use your phone to take a picture or to view it all together, but you have to be careful that you "minimize glimpsing the bright sun with your own eyes without the benefit of a proper filter".

Now the caution isn't coming from your camera filming the eclipse or taking pictures of the actual event. It won't damage your phone. The caution is coming from the reflection your phone is going to create from the sun onto your face. The reflection will be bright enough to cause some serious damage.

So in the end if you plan on using your phone to view the eclipse be careful. There is no need to ruin your vision or "cook or corneas" over a solar eclipse.