It proves to be a bluff charge, but there's no way of knowing whether that was the grizzly's intention all along or if he decided better of it halfway through its charge. But it might just be a blessing for the ranger that the bear was only running on three legs, slowing him down a bit.
Then, once the bear's bluff charge is stalled, the park ranger fires some shots at it - almost certainly employing bean bags or rubber non-lethal rounds in order to further deter the bear from attacking again. Before long, the bear decides that it really isn't worth it and runs back into the trees, much to the shock and entertainment of the family filming.
See the whole video below!