How to disable the Trackpad zoom in Chrome or TextEdit
I managed to disable it using BetterTouchTool (http://blog.boastr.net/) an awesome freeware app that lets you customize trackpad gestures on a per-app basis. I just added two gestures for chrome (one for pinch-out and one for pinch-in) and assigned no action to them. BTT overrides the OS's gesture recognition and disables pinch to zoom.
The pinch-to-zoom was conflicting with the other BTT gestures I set for Chrome (rotating gesture to switch tabs), and Chrome was always resizing my web pages whenever I switched tabs with my gesture. This trick ended it.
Trackpad zooming is an OS X wide functionality. You can enable/disable Trackpad zooming in System Preferences -> Trackpad