Changed return type of :ICore::mainWindow() to QWidget*

Also removed all <QMainWindow> includes which are not needed
anymore.

Change-Id: I393c9a62a5c6df95d9f35d872e1473a4f13bcdc4
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/coreplugin/actionmanager/command.cpp

@@ -39,7 +39,6 @@
 
 #include <QAction>
 #include <QShortcut>
-#include <QMainWindow>
 
 /*!
     \class Core::Command

src/plugins/coreplugin/basefilewizard.cpp

@@ -54,7 +54,6 @@
 
 #include <QMessageBox>
 #include <QWizard>
-#include <QMainWindow>
 #include <QIcon>
 
 enum { debugWizard = 0 };

src/plugins/coreplugin/editormanager/editormanager.cpp

@@ -78,7 +78,6 @@
 #include <QApplication>
 #include <QFileDialog>
 #include <QLayout>
-#include <QMainWindow>
 #include <QMenu>
 #include <QMessageBox>
 #include <QPushButton>

src/plugins/coreplugin/generalsettings.cpp

@@ -38,7 +38,6 @@
 #include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/icore.h>
 
-#include <QMainWindow>
 #include <QMessageBox>
 
 #include <QCoreApplication>

src/plugins/coreplugin/icore.cpp

@@ -513,7 +513,7 @@ IContext *ICore::currentContextObject()
 }
 
 
-QMainWindow *ICore::mainWindow()
+QWidget *ICore::mainWindow()
 {
     return m_mainwindow;
 }

src/plugins/coreplugin/icore.h

@@ -37,9 +37,9 @@
 #include <QSettings>
 
 QT_BEGIN_NAMESPACE
-class QMainWindow;
 class QPrinter;
 class QStatusBar;
+class QWidget;
 template <class T> class QList;
 QT_END_NAMESPACE
 
@@ -112,7 +112,7 @@ public:
     static QString resourcePath();
     static QString userResourcePath();
 
-    static QMainWindow *mainWindow();
+    static QWidget *mainWindow();
     static QStatusBar *statusBar();
 
     static IContext *currentContextObject();

src/plugins/coreplugin/manhattanstyle.cpp

@@ -47,7 +47,6 @@
 #include <QDockWidget>
 #include <QLabel>
 #include <QLineEdit>
-#include <QMainWindow>
 #include <QMenuBar>
 #include <QPainter>
 #include <QPixmap>