[WPE] WPE Platform: add WPEToplevel

[Carlos Garcia Campos]

Add a new class to handle platform toplevels. This will allow us to support multiple views in the same toplevel, but for now only one is supported.

[Carlos Garcia Campos]

Pull request: https://github.com/WebKit/WebKit/pull/30105

[EWS]

Committed 280412@main (af3cd7645c2f): <https://commits.webkit.org/280412@main>

Reviewed commits have been landed. Closing PR #30105 and removing active labels.

[[e-mail]]

Can I comment here to get help?

I got 2 errors for Qt6 build:

## 'wpe_view_resize' was not declared

```
Source/WebKit/UIProcess/API/wpe/qt6/WPEQtView.cpp:87:5: error: 'wpe_view_resize' was not declared in this scope; did you mean 'wpe_view_resized'?
|    87 |     wpe_view_resize(wpeView, d->m_size.width(), d->m_size.height());
|       |     ^~~~~~~~~~~~~~~
|       |     wpe_view_resized
```

## 'wpe_toplevel_qtquick' has not been declared

```
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp:35:46: error: 'wpe_toplevel_qtquick' has not been declared
|    35 | WEBKIT_DEFINE_FINAL_TYPE(WPEToplevelQtQuick, wpe_toplevel_qtquick, WPE_TYPE_TOPLEVEL, WPEToplevel)
|       |                                              ^~~~~~~~~~~~~~~~~~~~
| In file included from Source/WebKit/WPEPlatform/wpe/WPEView.h:36,
|                  from Source/WebKit/WPEPlatform/wpe/WPEEvent.h:35,
|                  from Source/WebKit/WPEPlatform/wpe/wpe-platform.h:31,
|                  from Source/WebKit/UIProcess/API/wpe/qt6/WPEDisplayQtQuick.h:30,
|                  from Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.h:29,
|                  from Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp:27:
| Source/WebKit/WPEPlatform/wpe/WPEToplevel.h:38:27: error: expected identifier before '(' token
|    38 | #define WPE_TYPE_TOPLEVEL (wpe_toplevel_get_type())
|       |                           ^
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp:35:68: note: in expansion of macro 'WPE_TYPE_TOPLEVEL'
|    35 | WEBKIT_DEFINE_FINAL_TYPE(WPEToplevelQtQuick, wpe_toplevel_qtquick, WPE_TYPE_TOPLEVEL, WPEToplevel)
|       |                                                                    ^~~~~~~~~~~~~~~~~
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp:37:1: error: expected constructor, destructor, or type conversion before 'static'
|    37 | static gboolean wpeToplevelQtQuickResize(WPEToplevel* toplevel, int width, int height)
|       | ^~~~~~
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp: In function 'void wpe_toplevel_qtquick_class_init(WPEToplevelQtQuickClass*)':
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp:52:29: error: 'wpeToplevelQtQuickResize' was not declared in this scope; did you mean 'WPEToplevelQtQuickClass'?
|    52 |     toplevelClass->resize = wpeToplevelQtQuickResize;
|       |                             ^~~~~~~~~~~~~~~~~~~~~~~~
|       |                             WPEToplevelQtQuickClass
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp: At global scope:
| Source/WebKit/UIProcess/API/wpe/qt6/WPEToplevelQtQuick.cpp:49:13: warning: 'void wpe_toplevel_qtquick_class_init(WPEToplevelQtQuickClass*)' defined but not used [-Wunused-function]
|    49 | static void wpe_toplevel_qtquick_class_init(WPEToplevelQtQuickClass* toplevelQtQuickClass)
|       |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

[[e-mail]]

For 'wpe_view_resize' was not declared, change to wpe_view_resized fixed

but for 'wpe_toplevel_qtquick' has not been declared, how to fix?