Bug 1044598 - Part 2: Make ServiceWorkerManager::GetServiceWorkerRegistration honor XPCOM rules; r=smaug

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extra : rebase_source : 6fcd656cae5db25b99c70a6d2c901409fb751755
Bug 1044598 - Part 3: Fix two refcounting errors in MediaRecorder code; r=roc

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extra : rebase_source : 6b817aa2949e5dca4dde171010dd7727ad03bd70