Have MessagePort use Oilpan-based weak pointers.
Using WeakPtr<>/WeakPtrFactory<> with Oilpan heap objects is problematic
in the face of lazy sweeping, WeakPtr<> references aren't cleared until
the finalizer runs. Should a posted task (like for MessagePort) run
before that happens, it might then access already finalized objects that
MessagePort refers to.
Hence WeakPtr<>s should not be used for Oilpan objects unless extra
finalization care is taken _and_ the object depends on WeakPtrFactory<>'s
support for explicit revocation. Use Oilpan weak references instead.
Also clear out various redundant WeakPtr.h includes throughout Blink.
R=haraken
BUG=522357
Review-Url: https://codereview.chromium.org/1922923003
Cr-Commit-Position: refs/heads/master@{#390105}
8 files changed
