Move DRM to CloseGuard, add DrmOutputStream.

Switch DrmManagerClient to using CloseGuard to better track leaked
resources.  Add DrmOutputStream which applies DRM transformation as
data is written, similar to FilterOutputStream.  Also writes DRM
headers before closing.

Change-Id: Ic106a3e6f6ff666e4dda484fbd234a0849eec8c0
2 files changed