Make QWindow's windowState a QFlags of the WindowState

This reflects QWidget API, and restores some behavior from Qt4.
Some WM can have several state at the same time. On Plasma for example,
when a window is both maximized and minimized, the "maximized" checkbox
is checked from the taskbar entry.

The API of QPlatformWindow was changed to take a QFlag and the platform
plugins were adapted.

 - On XCB: Always send the full state to the WM. And read the full state.

 - On Windows: The code was originally written with '&' in Qt4, and was changed
   to == when porting. Some adaptation had to be made so the states would be
   preserved.

 - On macOS: Only a single state can be set and is reported back for now,
   with the possibly to expand this in the future.

 - Other platforms: Just do as before with the effective state.

Task-number: QTBUG-57882
Task-number: QTBUG-52616
Task-number: QTBUG-52555
Change-Id: I7a1f7cac64236bbd4c591f796374315639233dad
Reviewed-by: Gunnar Sletta <gunnar@crimson.no>
Reviewed-by: Robin Burchell <robin.burchell@crimson.no>

2 files changed, 3 insertions, 3 deletions

diff --git a/src/platformsupport/fbconvenience/qfbwindow.cpp b/src/platformsupport/fbconvenience/qfbwindow.cpp
index 7e016f2f49..36f92b8cea 100644
--- a/src/platformsupport/fbconvenience/qfbwindow.cpp
+++ b/src/platformsupport/fbconvenience/qfbwindow.cpp
@@ -106,7 +106,7 @@ void QFbWindow::setVisible(bool visible)
     }
 }
 
-void QFbWindow::setWindowState(Qt::WindowState state)
+void QFbWindow::setWindowState(Qt::WindowStates state)
 {
     QPlatformWindow::setWindowState(state);
     mWindowState = state;
diff --git a/src/platformsupport/fbconvenience/qfbwindow_p.h b/src/platformsupport/fbconvenience/qfbwindow_p.h
index c201302a50..20bac46c69 100644
--- a/src/platformsupport/fbconvenience/qfbwindow_p.h
+++ b/src/platformsupport/fbconvenience/qfbwindow_p.h
@@ -70,7 +70,7 @@ public:
     void setGeometry(const QRect &rect) Q_DECL_OVERRIDE;
     void setVisible(bool visible) Q_DECL_OVERRIDE;
 
-    void setWindowState(Qt::WindowState state) Q_DECL_OVERRIDE;
+    void setWindowState(Qt::WindowStates state) Q_DECL_OVERRIDE;
     void setWindowFlags(Qt::WindowFlags type) Q_DECL_OVERRIDE;
     Qt::WindowFlags windowFlags() const;
 
@@ -93,7 +93,7 @@ protected:
     QFbBackingStore *mBackingStore;
     QRect mOldGeometry;
     Qt::WindowFlags mWindowFlags;
-    Qt::WindowState mWindowState;
+    Qt::WindowStates mWindowState;
 
     WId mWindowId;
 };