Vulkan: Remove implicit buffer barrier for shader write When app uses shaders to write to SSBO, right now we are inserting an implicit barrier to ensure WAW are in order. But Spec says that "Explicit synchronization is required to ensure that the effects of buffer and texture data stores performed by shaders will be visible to subsequent operations using the same objects". This CL removes the implicit barrier for buffer write if the current write comes from shaders and relies on explicit glMemoryBarrier to insert a global barrier. Bug: angleproject:350994515 Change-Id: I8ab039610be9be2ded27ea60dab54bdad08502f6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5719258 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Yuxin Hu <yuxinhu@google.com>