Revert "Remove support for MSVC"

This reverts commit d9cfbefcfe8710f1cb190ae817757853c8058797.

This CL broke android build:
http://build.chromium.org/p/client.mojo/builders/Mojo%20Android%20Builder%20%28dbg%29/builds/248

TBR=eseidel@chromium.org

Review URL: https://codereview.chromium.org/719063002