Revert r164107 - "Move remaining KeyCode files to platform/"

For some reason, this change breaks the build on the Android Debug Clang
bot downstream, and so was blocking the roll. It is not obvious what
is wrong w/ the change, so I was forced to revert it and file a bug :(.

TBR=pilgrim@chromium.org
BUG=329743

Review URL: https://codereview.chromium.org/118843003

git-svn-id: svn://svn.chromium.org/blink/trunk@164133 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move PageConsole from Page to FrameHost

The focus here was on replacing callers to
Page::console with FrameHost::console, but I also
replaced a few other page() callers with frameHost()
when possible.

PageConsole (despite it's confusing name) is mostly
just a wrapper around Chrome and knows how to
tell the ChromeClient to add a console message.

I also had to add a FrameHost::useCounter accessor
to avoid having to lookup both FrameHost and Page
separately in Document.cpp.

BUG=305811

Review URL: https://codereview.chromium.org/117733003

git-svn-id: svn://svn.chromium.org/blink/trunk@164134 bbb929c8-8fbe-4397-9dbb-9b2b20218538