Merge from Widevine repo of http://go/wvgerrit/53202
and
Merge from Widevine repo of http://go/wvgerrit/53624
This change contains a variety of small tweaks to the
ContentKeySession and EntitlementKeySession classes that were
discovered while fixing b/78652567. There should be no change in
behavior from this patch. The fixes are:
1) Added missing headers and removed unnecessary headers.
2) Removed the unused keys_ member from EntitlementKeySession.
3) Renamed ContentKeySession's protected member function so that it is
not an overload of the public LoadKeys() function. This makes it
clearer what EntitlementKeySession::LoadKeys() is doing.
4) Added missing "virtual" and "OVERRIDE" keywords.
5) Added missing copyright headers.
6) Ran clang-format with Google style.
7) Correct missing OVERRIDE keywords.
Test: tested as part of http://go/ag/4674759
Change-Id: Icb0af886d7d3eb097b5dffbb716be6ac28f0916d