Optimize BaseTextMark

Instead of each BaseTextMark being a QObject and being connected
to editorOpened, centralize that and distribute the signal
to only the BaseTextMarks that need it.

Change-Id: I3f2783c34a25d78aa335418236850436028bfdf3
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/plugins/valgrind/callgrindtextmark.cpp

@@ -47,9 +47,8 @@ using namespace Valgrind::Callgrind;
 
 CallgrindTextMark::CallgrindTextMark(const QPersistentModelIndex &index,
                                      const QString &fileName, int lineNumber)
-    : m_modelIndex(index)
+    : TextEditor::BaseTextMark(fileName, lineNumber), m_modelIndex(index)
 {
-    setLocation(fileName, lineNumber);
     setPriority(TextEditor::ITextMark::HighPriority);
 }