DOM: getting rid of JS_GetContextPrivate wherever possible. Use static parent
links where we can. When we do need to find this info about the caller
we call a function that knows how to get that info rather than inline calls
to JS_GetContextPrivate. This is all required for calling DOM objects on
non-DOM JSContexts as we do via xpconnect.
XPConnect: basic refactoring work to disassociate wrappers from the JSContext
that was active when the wrapper was constructed. This allows for calling into
wrapped JS objects on the right JSContext and for proper grouping of wrapped
native objects so that they can share proto objects. This also allows for
better sharing of objects and lays the foundations for threadsafety and
interface flattening.
Also, xpconnect tests are reorganized and improved.
fixes bugs: 13419, 17736, 17746, 17952, 22086
r=vidur r=mccabe r=norris r=cbegle
a=chofmann
