Debugger: Rework editor tooltips handling

Fix expansion and updating.

Persistence and non-locals are still lacking.

Change-Id: I74e25199d50350516afc686a05836e239bfc8acb
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/debugger/gdb/gdbengine.h

@@ -34,6 +34,7 @@
 
 #include <debugger/watchhandler.h>
 #include <debugger/watchutils.h>
+#include <debugger/debuggertooltipmanager.h>
 
 #include <coreplugin/id.h>
 
@@ -467,8 +468,7 @@ protected:
     void showExecutionError(const QString &message);
 
     static QByteArray tooltipIName(const QString &exp);
-    QString tooltipExpression() const;
-    QScopedPointer<DebuggerToolTipContext> m_toolTipContext;
+    DebuggerToolTipContext m_toolTipContext;
 
     // For short-circuiting stack and thread list evaluation.
     bool m_stackNeeded;