Bug 1011660 - Remove separate DOMClass struct. (r=bz)
Bug 727125 - Lazily compute LineBaselineOffset when needed so it is present after a dynamic change of 'text-decoration'. r=dbaron

This fixes the positioning of underlines set on a block or its ancestor
when drawn on children of a block that have a vertical-align !=
baseline.

The lazy computation is done all at once for all children of a block to
avoid O(N^2) searches for the line containing a frame.
Bug 727125 - Update overflow areas for text frames on text-decoration change to ensure text-decoration on hover is visible. r=dbaron
Bug 768395 - Crash in CDevice::DriverInternalErrorCB because the d3d device is set to crash on error instead of merely returning error codes. Explicitly set the exception mode on device creation, and assert it every time we get it again. r=jrmuizel