Reland "Move most of FrameLoader::CheckCompleted() to Document"
Split out the parts that are specific to the committed Document, and
move those to a new Document::CheckCompleted(). Most current callers of
FrameLoader::CheckCompleted() will now call Document::CheckCompleted()
instead. Rename the remainder of FrameLoader::CheckCompleted() to
DidFinishNavigation(), and have it handle the logic that is tied to
setting Frame::loading_ to false and firing DidStopLoading() callbacks.
Originally reviewed in https://codereview.chromium.org/2809733003/
BUG=
Review-Url: https://codereview.chromium.org/2837763003
Cr-Commit-Position: refs/heads/master@{#468030}
17 files changed
