Oilpan: Remove one reinterpret_cast from Handle.h
Oilpan: Remove one reinterpret_cast from Handle.h

This is just a small refactoring.
Instead of doing a mysterious reinterpret_cast to a Member<T>,
we can just call weakMember.get() to trace the weak member strongly.

BUG=420515

Review URL: https://codereview.chromium.org/781343004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@186708 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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