Move WriteBarrier operations into their own header file. Split Object.h

The write barrier routines will soon be INLINE and non-null.  Buried
in the middle of Object.h, which is early in Dalvik.h, it would be
hard for them to make use of definitions in other .h files.

Change-Id: I3c0eb59cb6ef29c2bacd0432cf59aaca4c3d031c
4 files changed