Pinch to Zoom Triggers Toolbar Behavior and Doesn't Zoom

[ekager]

Similar to #2695
See Fenix issue mozilla-mobile/fenix#2278
"Pinch to zoom trigger the address bar, even if the page doesn't scroll."

┆Issue is synchronized with this Jira Task

[Mugurell]

I think this issue stems from the fact that we don't have a clear way of knowing if the panning gesture was used for scrolling or for zooming. We treat both the same.

This explains why panning even with two fingers will animate the navbar.
But even one finger zoom will have the same effect.

We need to have a proper way to differentiate between this 2 gestures.