Renderer: Refactoring Frame DocumentAttached/DidAttachDocument (and spellfix)

- Renamed DocumentAttached() to DidAttachDocument() so that function names better express what the function is trying to accomplish
- Remove extraneous GetDocument() calls
- Spellfixing

"I think that DocumentAttached(..) is misleading, since it seems to imply that it's going to find out whether a document is attached and return a boolean representing that. Instead, it's in essence attaching to a document (or rather the document’s context, but with some clearing and such going on as well). Therefore, I'm thinking of perhaps renaming DocumentAttached(..) to AttachDocument(..) or AttachToDocument(..) in another CL." -Darwin in another CL

Bug: 896479
Change-Id: I4b9e2cd9a998f2b18acdbca9e2339c7ca5a124e8
Reviewed-on: https://chromium-review.googlesource.com/c/1300680
Commit-Queue: Darwin Huang <huangdarwin@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604366}
16 files changed