Initial scroll depth module logging depth corrrectly
Add content tracking to scrollDepth
Working scroll depth logging
Add unit test for scrollDepth module
Hook up scroll depth module with ophan record call
Fix spacing
Add feature switch for scroll depth
Amend switch text
Defend against divison by 0
Merge branch 'scroll-depth' of github.com:guardian/frontend into scroll-depth
Merge pull request #3044 from guardian/scroll-depth

Scroll depth measurement