Compute the shader hash without copying objects. The shader hash was calculated by generating a large string and then sha1 hashing the string. sha1 can be generated with a fixed memory cost using the angle::base::SecureHashAlgorithm class. Bug: angleproject:8434 Change-Id: I816e2c3bbc7283cd5424621b4cc8f6dab0407aa4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5073293 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>