android/utils/: Proper C++ inclusion guards.

This patch ensures that all headers under android/utils/ have proper
C++ inclusion guards, by using "android/utils/compiler.h" and the
macros it defines (ANDROID_BEGIN_HEADER / ANDROID_END_HEADER).

Just general cleanup before further work.

Change-Id: If37e346a1846af43bfd01dd7fc6999e188a6d025
18 files changed