Fix Automated API Review issues.

These API's argument/return value must be marked either @NonNull
or @Nullable.

Bug: 126701148
Bug: 126699090
Bug: 126701058
Bug: 126700772
Bug: 126699941
Bug: 126701299
Bug: 126700007
Test: atest FrameworksNetTests
Change-Id: I8a607d368aa6e2794b12a27b3fd032e1b99617a1
1 file changed