Bug 1022773 - Resolve hazard by switching Compile to MutableHandle, r=terrence, a=abillings

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extra : rebase_source : b87dd68a5921ac8c7ce2fc7751949d976304431d
extra : amend_source : 196ca8c8a9183ab5c57e23fe75b38854e778941c
extra : histedit_source : e1f49d32eb1da622227bc7f69303fdd74ec08fed
Bug 1022773 - Return value rooting for content/, r=smaug, a=abillings

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extra : rebase_source : 82f8d1fb785c20e523cdc56e3b59cc7c79d3f9fc
extra : histedit_source : a3a2cad397b2eb4fb3da960986fa6665e3434039
Bug 1022773 - Return value rooting for dom/, r=bz, a=abillings

--HG--
extra : rebase_source : 39a90c1a04a7bbe594750794836880d41bc2b278
extra : histedit_source : 4de73354f03fe6f12c04b857dd5c5e4c7d2bb726
Bug 1022773 - Return value rooting for workers, r=bent, a=abillings

--HG--
extra : rebase_source : 97b6db48e2329243f6e2f897fa82552123526816
extra : histedit_source : 9a795b69474814bcd27aef9909a75f3d63d506e8
Bug 1022773 - Return value rooting for JS engine, r=terrence, a=abillings

--HG--
extra : rebase_source : d9b8ec75bcaa843a5b60f8c757cdf0fc251631fe
extra : histedit_source : 5b8408f5d9f8d7542f887e42a3f66b62fdc2a535
Bug 1022773 - Return value rooting for XPConnect, r=bholley, a=abillings

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extra : rebase_source : fe6e37d8fb2366b9c50389f2d9e6417b3893d5bd
extra : histedit_source : 9b4cecbb66adcd05fe9215f99ba422715d28a19a
Bug 1022773 - Return value rooting for SPS, r=ehsan, a=abillings

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extra : rebase_source : ffacb5c8ed6a4349d248e2c1c2682da51e51a419
extra : histedit_source : 7730003b20d30ddc9710ebe883887d4f8f0532a2