Better Z-index support.

A bunch of changes related to window z-index:

- Keeps toplevel windows constrained in z-index between the desktop background (bottom-most) and the launcher (topmost).
- Renames WindowManager to EventFilter, and moves it to the parent Window... i.e. when a window receives a mouse event its parent's event filter will get the opportunity to process it before that window's delegate does.
- WindowManager's content was mostly specific to toplevel window movement, so this content moved to an EventFilter subclass called ToplevelEventFilter.
- Adds a name property to aura::Windows useful for debugging.
- Prevent Windows with no delegate from taking part in event processing.
- Initialize the Aura_Shell in DesktopWindow, provide a single exported method - aura_shell::InitDesktopWindow() - to initialize it from the exe main.

BUG=none
TEST=none
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=101974

[Ben Goodger (Google), 2011-09-19 23:15:33]

Testing forthcoming. I want to get some of the basics scoped out to unblock
other work.

[tfarina, 2011-09-20 02:18:01]

http://codereview.chromium.org/7970001/diff/5004/ui/aura/event_filter.h
File ui/aura/event_filter.h (right):

http://codereview.chromium.org/7970001/diff/5004/ui/aura/event_filter.h#newco...
ui/aura/event_filter.h:10: #include "ui/gfx/point.h"
remove these two unused includes and include basictypes instead for DISALLOW
macro?

[tfarina, 2011-09-20 02:19:24]

http://codereview.chromium.org/7970001/diff/5004/ui/aura/window.h
File ui/aura/window.h (right):

http://codereview.chromium.org/7970001/diff/5004/ui/aura/window.h#newcode63
ui/aura/window.h:63: string16 name() const { return name_; }
const string16& name() const { ... } ?

[oshima, 2011-09-20 05:29:28]

LGTM with 2 nits and 1 q.

http://codereview.chromium.org/7970001/diff/5004/ui/aura/desktop.h
File ui/aura/desktop.h (right):

http://codereview.chromium.org/7970001/diff/5004/ui/aura/desktop.h#newcode58
ui/aura/desktop.h:58: Window* toplevel_window_container() { return
toplevel_window_container_; }
() const {...

 same for getts above.

http://codereview.chromium.org/7970001/diff/5004/ui/aura/event_filter.h
File ui/aura/event_filter.h (right):

http://codereview.chromium.org/7970001/diff/5004/ui/aura/event_filter.h#newco...
ui/aura/event_filter.h:30: Window* owner() { return owner_; }
const

http://codereview.chromium.org/7970001/diff/5004/ui/aura/window.cc
File ui/aura/window.cc (right):

http://codereview.chromium.org/7970001/diff/5004/ui/aura/window.cc#newcode203
ui/aura/window.cc:203: delegate_->OnPaint(canvas);
no delegate means no texture means no paint request, correct?

[Ben Goodger (Google), 2011-09-20 17:08:23]

On Mon, Sep 19, 2011 at 10:29 PM, <oshima@chromium.org> wrote:

> LGTM with 2 nits and 1 q.
>
>
>
http://codereview.chromium.**org/7970001/diff/5004/ui/aura/**desktop.h<http:/...
> File ui/aura/desktop.h (right):
>
> http://codereview.chromium.**org/7970001/diff/5004/ui/aura/**
>
desktop.h#newcode58<http://codereview.chromium.org/7970001/diff/5004/ui/aura/desktop.h#newcode58>
> ui/aura/desktop.h:58: Window* toplevel_window_container() { return
> toplevel_window_container_; }
> () const {...
>

They can't be const because the returned Window object is (necessarily)
non-const. Same for the other.

http://codereview.chromium.**org/7970001/diff/5004/ui/aura/**
>
window.cc#newcode203<http://codereview.chromium.org/7970001/diff/5004/ui/aura/window.cc#newcode203>
> ui/aura/window.cc:203: delegate_->OnPaint(canvas);
> no delegate means no texture means no paint request, correct?
>
> Correct. We should crash in this case :-)

-Ben

[oshima, 2011-09-20 17:48:03]

On Tue, Sep 20, 2011 at 10:08 AM, Ben Goodger (Google) <ben@chromium.org>wrote:

> On Mon, Sep 19, 2011 at 10:29 PM, <oshima@chromium.org> wrote:
>
>> LGTM with 2 nits and 1 q.
>>
>>
>>
http://codereview.chromium.**org/7970001/diff/5004/ui/aura/**desktop.h<http:/...
>> File ui/aura/desktop.h (right):
>>
>> http://codereview.chromium.**org/7970001/diff/5004/ui/aura/**
>>
desktop.h#newcode58<http://codereview.chromium.org/7970001/diff/5004/ui/aura/desktop.h#newcode58>
>> ui/aura/desktop.h:58: Window* toplevel_window_container() { return
>> toplevel_window_container_; }
>> () const {...
>>
>
> They can't be const because the returned Window object is (necessarily)
> non-const. Same for the other.
>

const method can return non const object. Is it banned in chromium?


> http://codereview.chromium.**org/7970001/diff/5004/ui/aura/**
>>
window.cc#newcode203<http://codereview.chromium.org/7970001/diff/5004/ui/aura/window.cc#newcode203>
>> ui/aura/window.cc:203: delegate_->OnPaint(canvas);
>> no delegate means no texture means no paint request, correct?
>>
>> Correct. We should crash in this case :-)
>
> -Ben
>

[Ben Goodger (Google), 2011-09-20 17:55:49]

On Tue, Sep 20, 2011 at 10:47 AM, oshima <oshima@chromium.org> wrote:

> They can't be const because the returned Window object is (necessarily)
>> non-const. Same for the other.
>>
>
> const method can return non const object. Is it banned in chromium?
>
> Not banned so much as not preferred... it violates the "logical const-ness"
of the object. pkasting can give a good rundown on the details :-)

When you want to return a const object we prefer:

const Foo* foo() const { .. }

... but I haven't needed a const getter yet.

Have been incrementally migrating views to this format as well.

-Ben