Implement support for origin-TopLeft render targets. Note that the default behaviour remains the same: textures default to origin-TopLeft, render targets default to origin-BottomLeft, and backend textures default to origin-BottomLeft. However, the caller can override the default by setting fOrigin in GrTextureDesc, GrBackendTextureDesc or GrBackendRenderTargetDesc.
Review URL: https://codereview.appspot.com/
7230049
git-svn-id: http://skia.googlecode.com/svn/trunk@7594
2bbb7eff-a529-9590-31e7-
b0007b416f81