Remove workaround for Visual Editor bug (T53150).

This bug has been fixed in Visual Editor for over a year.  Let's not haul
around unnecessary cruft in our codebase.

Bug: T53150
Change-Id: I2d9e0f0c1ac7aee3a093a67f42d0193a3f195117
Merge "Remove workaround for Visual Editor bug (T53150)."