Vulkan: Sync pipeline cache only when truly changed The Vulkan pipeline cache was considered dirty when ANGLE added a new pipeline. However, a new pipeline doesn't necessarily translate to new blobs in the pipeline cache. With this change, the cache is synced only if its size has changed. Bug: angleproject:5881 Change-Id: I0226426680f1e6b0e2bfde66ea6409362b8e72c9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3668835 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>