Bug 915167 - Don't create helper threads when GetCPUCount() == 1 (r=bhackett)

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extra : rebase_source : 2bdf6c0df177361d004f63162dbe219665a3a269
Bug 901560 - Interim fix of datachannel ICE components to be compatible with old and new versions r=abr
Bug 914547 Ensure the DirectX headers can be found when necessary r=jgilbert
Bug 903285 - Add referent count reporting to pref service memory reporter. r=njn
Bug 856437 - Remove LookupMethod test coverage. r=gabor
Bug 856437 - Remove lookupMethod API. r=gabor
Bug 856437 - Remove same-compartment permissive Xray machinery. r=gabor