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

Includes:
be8e087 Travis: download and install pip
4f36a64 Force binary mode when writing a binary to stdout
87a8420 Adjust configuration to link SPIRV-Tools into Glslang

Change-Id: I3913a24661c82c3c601474af4b3e4d9dccafd1ec
Testing: checkbuild.py on Linux; unit tests on Windows