Merge of these CLs from Widevine sc-dev:
modified: libwvdrmengine/level3/include/clear_cache_function.h
Add cache flush assembly for arm64 L3 to Android header | http://go/wvgerrit/124828
Address compilation errors | http://go/wvgerrit/113083
modified: libwvdrmengine/level3/include/level3_file_system_android.h
Update Widevine Copyright header for android | http://go/wvgerrit/108084
Bug: 184866351
Test: Header changes for clearing cache is verified by one of the partners on their arm64 target;
https: //b.corp.google.com/issues/175432203#comment13
Change-Id: I0ac8f339f65d02abb3080020fbc715b9c0db85b2
d542cb91b5