I have recently experienced the same issue. All of our Flex apps will now not respond (zoom) to scroll wheel in Chrome. This is multiple workstations with the following configuration:
Windows 7 SP1
Chrome 37.0.2062.103
Adobe Flash Player 14.0.0.177
Apps are on Flex 3.6
I have tried clearing browser history, rebooting, can't re-install Chrome very easily as our workstation environments are locked down from uninstalling/reinstalling.
The holding down the Ctrl button to initialize zoom behaviors did work - but something did change / break recently within Chrome and Flex.
Glenn