Add a specialized apps::NativeAppWindow for app_shell

Add a specialized apps::NativeAppWindow for app_shell

ShellNativeAppWindow is a minimal views-based v2 app window. It is always
centered, cannot be resized, and has no frame. However, it can be created
without src/chrome dependencies.

This allows app_shell to open an app window using chrome.app.window.create()

BUG=341251
TEST=existing browser_tests of apps

[James Cook, 2014-02-13 01:13:35]

benwells, PTAL

I kept the awful ShellShellWindowDelegate name for now. I figure I can fix it
when I rename ShellWindow to AppWindow -- it seemed bad to mix the two names.

https://codereview.chromium.org/145723011/diff/20001/apps/apps_client.h
File apps/apps_client.h (right):

https://codereview.chromium.org/145723011/diff/20001/apps/apps_client.h#newco...
apps/apps_client.h:36: virtual ShellWindow* CreateShellWindow(
I really only need the delegate, but I elected to return ShellWindow because it
can be forward declared. I can extract ShellWindow::Delegate to its own class,
but that will also require extracting ShellWindow::CreateParams to its own class
and doing that felt a little big for this CL.

[benwells, 2014-02-14 06:53:25]

On 2014/02/13 01:13:35, James Cook wrote:
> benwells, PTAL
> 
> I kept the awful ShellShellWindowDelegate name for now. I figure I can fix it
> when I rename ShellWindow to AppWindow -- it seemed bad to mix the two names.
> 
> https://codereview.chromium.org/145723011/diff/20001/apps/apps_client.h
> File apps/apps_client.h (right):
> 
>
https://codereview.chromium.org/145723011/diff/20001/apps/apps_client.h#newco...
> apps/apps_client.h:36: virtual ShellWindow* CreateShellWindow(
> I really only need the delegate, but I elected to return ShellWindow because
it
> can be forward declared. I can extract ShellWindow::Delegate to its own class,
> but that will also require extracting ShellWindow::CreateParams to its own
class
> and doing that felt a little big for this CL.

Sorry I've been so slow to look at this. I'm getting the old 'old chunk
mismatch' problem when I look at the diffs...