When we detect that shader from our on-disk cache is invalid, we correctly skip loading it. However, we leave the shader in the cache, meaning that on each subsequent restart of Chrome we will try and fail to load it.

This both wastes resources, as well as making it hard to assess the true number of shaders which are failing our checks (as UMAs keep re-counting the same bad shaders on each load).

We should update the on-disk cache to evict a shader if it fails to load. We might also consider evicting the entire cache if any shader fails to load, as the most common case of this is a version change, which will invalidate all shaders.