Revert "Revert "Revert "Do not draw background or line in toolbars if the color scheme has no headers group"""

This reverts commit 2f1fc86a13 on master only, as it was targeted for Plasma/5.21, not master.

kstyle/breezestyle.cpp

@@ -950,7 +950,7 @@ namespace Breeze
     bool Style::drawWidgetPrimitive( const QStyleOption* option, QPainter* painter, const QWidget* widget ) const {
         Q_UNUSED(option)
         auto parent = widget;
-        if (!_toolsAreaManager->hasHeaderColors() || !_helper->shouldDrawToolsArea(widget)) {
+        if (!_helper->shouldDrawToolsArea(widget)) {
             return true;
         }
         auto mw = qobject_cast<const QMainWindow*>(widget);

kstyle/breezetoolsareamanager.cpp

@@ -121,8 +121,6 @@ namespace Breeze {
                 }
             }
         }
-
-        _colorSchemeHasHeaderColor =  KColorScheme::isColorSetSupported(_config, KColorScheme::Header);
     }
 
     bool AppListener::eventFilter(QObject *watched, QEvent *event)
@@ -241,9 +239,4 @@ namespace Breeze {
             _windows[mainWindow].removeAll(toolbar);
         }
     }
-
-    bool Breeze::ToolsAreaManager::hasHeaderColors()
-    {
-        return _colorSchemeHasHeaderColor;
-    }
 }

kstyle/breezetoolsareamanager.h

@@ -37,7 +37,6 @@ namespace Breeze {
         KConfigWatcher::Ptr _watcher;
         QPalette _palette = QPalette();
         AppListener* _listener;
-        bool _colorSchemeHasHeaderColor;
 
         friend class AppListener;
 
@@ -59,8 +58,6 @@ namespace Breeze {
         void unregisterWidget(QWidget *widget);
 
         QRect toolsAreaRect(const QMainWindow *window);
-
-        bool hasHeaderColors();
     };
 }