Oilpan: use transition types for remaining RefPtr<Document>s in dom/.

Switch to RefPtrWillBeRawPtr<>/RefPtrWillBeMember<> instead.

R=haraken@chromium.org
BUG=357163

Review URL: https://codereview.chromium.org/301233010

git-svn-id: svn://svn.chromium.org/blink/trunk@175316 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Convert page-level classes to handle RemoteFrames from FrameTree

Several classes iterate through the FrameTree for some page-related
behavior. They now need to be able to handle the situation where some
nodes in the tree are RemoteFrames.

R=dcheng@chromium.org
BUG=346764

Review URL: https://codereview.chromium.org/302213002

git-svn-id: svn://svn.chromium.org/blink/trunk@175317 bbb929c8-8fbe-4397-9dbb-9b2b20218538