Debugger: Add infrastructure for message tracepoints.

Add context menu to add a 'message tracepoint', that is,
a trace point that outputs a user message and continues.
Intended to be a replacement for manually inserting
a qDebug() into the code to understand the call sequence.
Yet to be implemented for gdb.

Change-Id: I1c303001421fbbae74d98d15d52718579350db6e
Rubber-stamped-by: hjk
Reviewed-on: http://codereview.qt.nokia.com/756
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

src/plugins/debugger/watchutils.cpp

@@ -678,6 +678,14 @@ QString cppExpressionAt(TextEditor::ITextEditor *editor, int pos,
     return expr.toUtf8();
 }
 
+QString cppFunctionAt(const QString &fileName, int line)
+{
+    using namespace CppTools;
+    using namespace CPlusPlus;
+    CppModelManagerInterface *modelManager = CppModelManagerInterface::instance();
+    return AbstractEditorSupport::functionAt(modelManager,
+                                             fileName, line, 1);
+}
 
 //////////////////////////////////////////////////////////////////////
 //