Add gypi file per folder.

This patch moves introduces a gypi file per folder. The gypi file
includes files in that folder, instead of having all of them in
ozone_impl.gyp. Now, Desktop Aura related files are compiled only
when toolkit_views = 1. This has resulted in a linking error when
Toolkit views is disabled but will be fixed in coming up patches.
Move all desktop_* and related files to desktop_aura folder.
Move keyboard_engine_xkb to wayland/input/

keyboard_engine_xkb has dependencies on XKB and is used by wayland/.
This patch moves keyboard_engine_xkb to wayland and removes wayland/
dependency on ime/
desktop_aura: Track upstream changes in DWTHWayland
wayland: Add more useful warnings about not implemented code
desktop_aura: Treat TYPE_BUBBLE similar as TYPE_WINDOW

App Launcher is one of the few bubble types I've seen and seems that it pretty
much imitates the window type behavior (toplevel). Treat these types equally
for now, therefore.

TEST=./out/Debug/chrome --no-sandbox --user-data-dir=/tmp/chrome --show-app-list
BUG=#197