clang-format: Tweak -style=Chromium for Java files.

For Java, don't do any of the deviations from Google Style that Chromium style
does for C++.

Chromium's Java follows Android Java style [1], which is roughly Google Java
style with an indent of 4 and a continuation indent of 8.

1: https://source.android.com/source/code-style.html
llvm-svn: 222839