For whatever reason "objdump.exe -t xicontent.o" on Windows now
lists Start@ScRefreshTimer@@EAEXXZ (probably because it's now
a virtual function). Also the reference to SetRefreshDelay
vanished after dropping the virtual keyword from SetRefreshDelay.

The linux object file doesn't even refer to a ScRefreshTimer
function. Start() can stay private, as the timer is handled via
SetRefreshDelay.

Probably Stop() should also become private in this case.

This also reverts 2c0189a8

Change-Id: I2a6900cd6bd76c4fec9f30131152b60a5bd2c2e7