Bug 887791 - Add MacIOSurfaceImage. r=roc
Bug 887791 - Add a TextureClient implementation for MacIOSurface. r=nical
Bug 887791 - Add a TextureHost implementation for MacIOSurface. r=nical
Bug 887791 - Implement ISharedImage for MacIOSurfaceImage. r=nical
Bug 887791 - Use the MacIOSurface TextureClient/Host for sharing MacIOSurface objects. r=roc
Bug 887791 - Remove a bunch of now-unused SharedTextureHandle code. r=roc