Grey overlay in mobile Safari

[blasten]

Moved from PolymerElements/paper-drawer-panel#75

Gesture events such as tap and track also attach a click and mousedown event handlers. This will result in a grey overlay in mobile safari.

We could remove those listeners if possible or use:

-webkit-tap-highlight-color: rgba(0,0,0,0);
-webkit-touch-callout: none;

Ref: http://stackoverflow.com/questions/5106934/prevent-grey-overlay-on-touchstart-in-mobile-safari-webview

[frankiefu]

This is the POC fix for the issue: 078f358

[addyosmani]

@frankiefu If I understand correctly, the POC in 078f358 negates the need to use the -webkit-tap-highlight-color workaround on body, right? We're running into this issue in PSK and might hold out for the upstream fix rather than monkey-patching in the short term.

[blasten]

@addyosmani right!