Remove Sub-Licenses and Sub-Sessions

(This is a merge of http://go/wvgerrit/66643)

The sub-license feature has been removed from the server and packager.
So that we do not have to continue maintaining the code that supports
this feature that never shipped, I am removing it from the CDM as well.

Bug: 113165466
Test: CE CDM Unit Tests
Test: Android Unit Tests
Change-Id: I5d25844b161e74aa19adf19a29c56e4881aa7304

libwvdrmengine/cdm/core/src/initialization_data.cpp

@@ -85,15 +85,6 @@ InitializationData::InitializationData(const std::string& type,
   }
 }
 
-// Parse the pssh data and return the embedded key data if it exists.
-std::vector<video_widevine::SubLicense>
-InitializationData::ExtractSublicenseKeys() const {
-  std::vector<video_widevine::SubLicense> keys;
-  // TODO(jfore): The pssh has changed in ways that are not compatible with
-  //sublicenses. Restructure or remove sublicense support including this method.
-  return keys;
-}
-
 std::vector<video_widevine::WidevinePsshData_EntitledKey>
 InitializationData::ExtractWrappedKeys() const {
   std::vector<video_widevine::WidevinePsshData_EntitledKey> keys;