Moves the last references to HLSLBlockEncoder out of ProgramBinary. Only one reference to ShaderD3D remains.

BUG=angle:731
Change-Id: Ie23e24e09fbed4c8c5fab3bab814b7092a383c7f
Reviewed-on: https://chromium-review.googlesource.com/220940Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Brandon Jones <bajones@chromium.org>