(This is a merge of http://go/wvgerrit/74628)
There is some old legacy behavior in CryptoSession for supporting
Chromecast. When a platform tries to use a combination of L3 and opaque
handles, it silently substitutes the type "clear buffers" instead.
No platform uses this behavior anymore. In fact, the CE CDM contains
code that explicitly prevents this case from being triggered. That code
has broken in every one of the last 3 releases. To allow the CE CDM to
end that bug farm, this patch removes the behavior that no one wants.
Bug: 112703532
Test: CE CDM Unit Tests
Test: Android Unit Tests
Change-Id: I7f70483fac46c75637da5378c5a8b1bf7a2c2860