To better facilitate testing device scale factor, we should be able to override it per view. Related to rdar://problem/18727850.
Created attachment 246135 [details] Patch
Created attachment 246137 [details] Patch
Created attachment 246169 [details] Patch
Comment on attachment 246169 [details] Patch CGFloat please!
Committed r179752 with CGFloat. https://trac.webkit.org/r179752