[ Merge from http://go/wvgerrit/16498 ]
The CDM now supports AES CTR and CBC block cipher modes. The license
specifies the mode to be used in the key container. The mode is
also specified in mediaCrypto when calling decrypt. This adds
verification for the cipher block mode.
Change-Id: I2587fc1e4b6d77161f2f8653f8516024c73dd8ac