Refactor framebuffer clear to be less redundant
Refactor framebuffer clear to be less redundant

Bug: b/119621736
Change-Id: I8a25e6a5dba7e05649c35dc65160f69300bf5791
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/35508
Tested-by: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>
Presubmit-Ready: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>
Kokoro-Presubmit: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader