Make all v1 app windows use the same maximized window frame

Make all v1 app windows use the same maximized window frame.

BUG=297174
TEST=None

[pkotwicz, 2013-10-01 17:39:48]

Steven, can you please take a look? To the extent of my knowledge the special
behavior was added to support panels. Panels have since dramatically changed.
(Notably PanelFrameView)
Do you know of any reason we want to keep the special behavior?
The main reason that I want to make this change is that I am in the process of
making v2 apps use the same maximized app frame as v1 apps.

[stevenjb, 2013-10-01 18:59:05]

On 2013/10/01 17:39:48, pkotwicz wrote:
> Steven, can you please take a look? To the extent of my knowledge the special
> behavior was added to support panels. Panels have since dramatically changed.
> (Notably PanelFrameView)
> Do you know of any reason we want to keep the special behavior?
> The main reason that I want to make this change is that I am in the process of
> making v2 apps use the same maximized app frame as v1 apps.

This affects extension 'popups' too. A browser window opened by an extension
(with windows.open or chrome.window.open) has is_app() == true. Without the
app_type() test we will treat the window like a v1 app opened as a window,
rather than like a regular browser window. That seems like it's OK, especially
since this only affects maximized behavior, but it's something we should be
aware of.

If we do this, we should get rid of Browser::AppType entirely since it's no
longer used anywhere else, which is not a bad thing in my mind.

[pkotwicz, 2013-10-27 23:40:12]

I am closing this CL because we have changed the design of the window frame for
v1 apps. I will post a doc outlining the design of the window frame for v1 and
v2 apps on Monday