Bug 663263 part A - Modify some code in nsReadableUtils to support fallible and infallible variations of AppendUTF8toUTF16, r=jlebar a=lsblakk

--HG--
extra : rebase_source : 3d95e51ee9c9421d553c2fcded39207512ef88fa
Bug 836263 part B - Do custom OOM error reporting in nsPrefBranch::GetComplexValue in the hopes of better diagnosis of a topcrash correlated to a few addons but otherwise very mysterious, r=khuey/ted a=lsblakk

--HG--
extra : rebase_source : 794b5385a82178fd70325dacffbc359ea869f046