GitLab

- In CdmAdapter, do not expose a Decryptor is CdmProxy is requested.
- In MojoCdm, support CDM ID based Decryptor in MojoCdm.
- Implement ClearKeyCdmProxy::SetKey() to load a license in its
  AesDecryptor so it can perform decryption.
- Update ECKEncryptedMediaTest.CdmProxy test to cover playback using
  ClearKeyCdmProxy to do decryption.

TBR: rkuroiwa@chromium.org
Bug: 806018
Test: ECKEncryptedMediaTest.CdmProxy covers the new path
Change-Id: Icd1cbddb8535f9b2ef5b20c3b1535d8c41dbb19c
Reviewed-on: https://chromium-review.googlesource.com/1071073
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: John Rummell <jrummell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562537}