Bug 1001198 - Explicitly fire up the SSM from nsXPConnect. r=gabor
Bug 1001198 - Stop firing onNewGlobalObject for the SafeJSContext global. r=gabor
Bug 1001198 - Remove the call to InitClasses for the SafeJSContextGlobal. r=gabor

In contrast to InitClassesWithNewWrappedGlobal, InitClasses doesn't do much
these days. It pretty much only exists to support JSD globals that are created
without XPConnect's knowledge, and then are suddenly handed to XPConnect.

It really only has two observable effects. The first is ensuring the existence
of an XPCWrappedNativeScope, which we know we have here, because we went through
xpc::CreateGlobalObject. The second is to set up the XPCNativeWrapper
constructor (eww), which definitely doesn't matter here, especially now that
we're asserting that we never run script in this global.
Bug 1001198 - Remove useless (and footgun) XPCWrappedNativeScope::InitStatics. r=gabor

All this does is null out some stuff that's already in the BSS. And it causes
leaks if we create a global before it's called, which the upcoming patch does.
Bug 1001198 - Explicitly create the SafeJSContext from XPConnect. r=gabor
Bug 1001198 - Stop getting XPConnect as a service during Sandbox creation. r=gabor

This causes problems when we try to create a Sandbox during XPConnect
initialization. Luckily, we don't need it at all.
Bug 1006629 - Remove GetCalleeWrapper. r=gabor
Bug 1006629 - Remove unused mFlattenedJSObject from XPCCallContext. r=gabor