GitLab

GlobalFetch::ScopedFetcher instances are heap objects, so avoid using
WeakPtr<>s over those.

Also switch over to using WeakPtr* transition types where possible.

R=haraken
BUG=509911

Review URL: https://codereview.chromium.org/1320563003

git-svn-id: svn://svn.chromium.org/blink/trunk@201305 bbb929c8-8fbe-4397-9dbb-9b2b20218538