Add explicit OMAP support to dump_syms.

This CL adds new utilities to common/windows for handling OMAP information in
PDB files. It then augments PdbSourceLineWriter with explicit OMAP knowledge so
that symbolization will proceed more cleanly for images whose PDB files contain
OMAP information. This makes breakpad handle OMAPped symbol files as cleanly as
WinDbg.

Review URL: https://breakpad.appspot.com/570002/



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1167 4c0a9323-5329-0410-9bdc-e9ce6186880e