Fix (most) generated includes to have gen/ in their path.
This makes it easier to tell where files exist on disk.
Unfortunately I had to leave the old include path
in engine/BUILD.gn to support all the v8 includes
which were too many to deal with in this patch.
It's a little nasty to have the raw build directory
in our include path, but it produces nicer paths.
R=abarth@chromium.org
We only allow overflow scrolling. The frame isn't special.
This is a first step in making that happen. There's a lot of
code to remove after this patch, but this gets rid of
ScrollView and a bunch of frame-level scrolling code.
Had to add in a FrameWidget class so that Scrollbar.cpp had
a way of getting to FrameView::removeChild without pulling
a core class into platform. This might go away when we rip
out the Widget tree if we made it so that FrameView didn't
keep a list of Scrollbar instances.
Modified scrollbar.html to use overflow scrolling instead of
frame level scrolling. Once we get rid of the split between
Document and documentElement, we'll be able to make the root
element in the page scrollable as well (i.e. any child of the
Document).
R=abarth@chromium.org
Review URL: https://codereview.chromium.org/646273006
