Adds the interfaces for MicrodumpProcessor (very similar to
MinidumpProcessor) and corresponding unittest stubs.
These stubs are required for multi-side integration and to start
rolling the updated processor library into the dependent projects.
BUG=chromium:410294
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1372 4c0a9323-5329-0410-9bdc-e9ce6186880e
