Google Chrome's emulation feature requires you to enter the device resolution and the device pixel ratio. It has presets for iPhone 5 but not for iPhone 6 or iPhone 6+ yet.
Do you know what resolution and pixel ratio I should be entering for iPhone 6?
I've been looking for the same thing, until the new update comes out with the models added I've been going by this link http://www.paintcodeapp.com/news/iphone-6-screens-demystified here.
Although fair warning it's not perfect, I've got an iphone 6 in front of me and although it's close, it's not exact.
