Remove LocalFrameLifecycleObserver::willDetachFrameHost()
willDetachFrameHost() is dispatched at almost the same timing as contextDestroyed().
Hence this CL replaces willDetachFrameHost() with contextDestroyed().
The only exception is LocalDOMWindow::willDetachFrameHost().
It needs to be called before the frame is actually detached from the frame host,
so this CL moves the contents to LocalFrame::detach().
BUG=610176
Review-Url: https://codereview.chromium.org/2142753002
Cr-Commit-Position: refs/heads/master@{#404924}
17 files changed
