Clear Content Copy

Copy from Widevine repository of http://go/wvgerrit/13841

This CL adds a nonblocking CopyBuffer to OEMCrypto, its unit tests,
and plumbs it up to the cdm CryptoSession and CdmEngine.

b/19543782

Change-Id: I4c88bd2f8d7f67ecccb549c1934b7c0da15a8429

libwvdrmengine/cdm/core/include/oemcrypto_adapter.h

@@ -13,6 +13,9 @@ enum SecurityLevel { kLevelDefault, kLevel3 };
    If one level is not available, the other will be used instead. */
 OEMCryptoResult OEMCrypto_OpenSession(OEMCrypto_SESSION* session,
                                       SecurityLevel level);
+OEMCryptoResult OEMCrypto_CopyBuffer(
+    SecurityLevel level, const uint8_t* data_addr, size_t data_length,
+    OEMCrypto_DestBufferDesc* out_buffer, uint8_t subsample_flags);
 OEMCryptoResult OEMCrypto_InstallKeybox(const uint8_t* keybox,
                                         size_t keyBoxLength,
                                         SecurityLevel level);