Removes the concept of a configurable "default" interface and makes the default
always be the "native" interface.
Also removes unused functions: GrGLInterfaceAddTestDebugMarker and
GrGLInterface::NewClone.
Keeps around legacy GrGLCreateNativeInterface() until clients can be weened.
Change-Id: I4a3bdafa8cf8c68ed13318393abd55686b045ccb
Reviewed-on: https://skia-review.googlesource.com/83000
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
3d6801eeee