caller-implemented SymbolSupplier object to get a symbol file.
Add a CrashReportProcessor object which provides a simple API for processing
a CrashReport struct, given a SymbolSupplier and a minidump file.
r=mmentovai (#17))
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@18 4c0a9323-5329-0410-9bdc-e9ce6186880e
