Revert of Improve tracking of bound FBOs in GrGLGpu. (patchset #8 id:140001 of https://codereview.chromium.org/949263002/) Reason for revert: breaking things Original issue's description: > Improve tracking of bound FBOs in GrGLGpu. > > Committed: https://skia.googlesource.com/skia/+/d2ad8eb5801e2c8c0fa544a6a776bb46eedde2a0 > > Committed: https://skia.googlesource.com/skia/+/b2af2d8b83ca4774c3b3bb1e49bc72605faa9589 TBR=egdaniel@google.com NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true Review URL: https://codereview.chromium.org/963973002