Merge remote-tracking branch 'aosp/upstream-master' into update-shaderc

Includes:
2bb92e6 Fix #45, and minor reordering.
95579e1 Merge pull request #46 from dneto0/regsiter-spirv-tools-linker
d73476e Register the Khronos SPIRV-Tools Linker

Test: checkbuild.py on Linux; unit tests on Windows
Change-Id: I7032466fea49e5aeb651ce29c690eaec80eb66b6