This change allows the app to specify that keys may be shared by sessions. The app enables this by setting the session sharing properties in DRM Plugin. Keys are shared only amoungst the specified group of sessions. Merged from widevine CDM repo * https://widevine-internal-review.googlesource.com/#/c/8019/ * https://widevine-internal-review.googlesource.com/#/c/8021/ Bug: 11013707 Change-Id: I52db41a53138b4fc563ebc6d38a623f23f7cdfb5