Bug 891660. Add support for Azure on Mac with OMTC. r=mattwoodrow

This is not the best approach but it works for now.  We basically pull the cg
context from gfxASurface and wrap a DrawTarget around it. In the end we'll need
to plumb the DrawTarget through more.

--HG--
rename : dom/ipc/PTabContext.ipdlh => dom/ipc/PContent.ipdl
extra : rebase_source : 49eac0354864ae9f2e7434b8b1efacc37d69fc23
Bug 889094 - NPE in BrowserToolbar due to late initialization of mFocusOrder. [r=sriram,bnicholson]
Bug 889555 - Force hiding awesomebar's action-bar during onCreate(). [r=sriram]