Fix zooming in fullscreen mode

Fix zooming in fullscreen mode

[Issue] After opening HTML element in fullscreen mode
with element.requestFullScreen() method, browser allowed
to zoom in and out content under fullscreen layer. It caused
incorrect display of the top layer.

[Solution] Disable pinch events (which are responsible for zooming)
when web_contents is in fullscreen mode or
in case that they are disabled with switch --disable-pinch.

Task: CBWEBCORE-136
Change-Id: I5891f07fee141e0975f90f95f43e708f67eb4dff