Introduced a QML-specific debugger tool bar

This one has the common debugger actions as well as the QML Observer
specific part. This makes sure those actions are generally available and
not only from the QML Observer dock widget.

The filter in the tool bar should still be moved back.

Reviewed-by: Christiaan Janssen <christiaan.janssen@nokia.com>

src/plugins/debugger/debuggerplugin.cpp

@@ -391,7 +391,6 @@ const char * const BREAK_AT_MAIN            = "Debugger.BreakAtMain";
 // Don't add '1' to the string as it shows up in the shortcut dialog.
 const char * const ADD_TO_WATCH1            = "Debugger.AddToWatch";
 const char * const ADD_TO_WATCH2            = "Debugger.AddToWatch2";
-const char * const OPERATE_BY_INSTRUCTION   = "Debugger.OperateByInstruction";
 const char * const FRAME_UP                 = "Debugger.FrameUp";
 const char * const FRAME_DOWN               = "Debugger.FrameDown";
 
@@ -3276,6 +3275,11 @@ DebuggerMainWindow *DebuggerPlugin::mainWindow()
     return theDebuggerCore->m_mainWindow;
 }
 
+QAction *DebuggerPlugin::visibleDebugAction()
+{
+    return theDebuggerCore->m_visibleDebugAction;
+}
+
 QWidget *DebugMode::widget()
 {
     if (!m_widget) {