Adapt unpaged cursors to paged requests.

Allow all client targeting Android O to assume paging
    support for any provider.
Adds a new PageViewCursor that adapts an unpaged cursor
    to a paged request.
Updates ContentProviderNative to perform wrapping on
    unpaged results.

Bug: 30927484
Change-Id: I4e225dc16761793c85ef8a195bf049113c79cd20
Test: Added for new class. Run info @ frameworks/base/core/tests/coretests/README