Find: Display "This change cannot be undone" only once.

Every click on Search Again displayed an additional warning message bar.

If the bar is closed with the cross button, it reappears on Search
Again.

This implementation extended InfoBar with a reuseable method
bool containsInfo(const QString &id).

Task-number: QTCREATORBUG-6873

Change-Id: I1de100d3526b861fc2de190e32f903795fed52c0
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/plugins/coreplugin/infobar.cpp

@@ -91,6 +91,16 @@ void InfoBar::removeInfo(const QString &id)
         }
 }
 
+bool InfoBar::containsInfo(const QString &id) const
+{
+    QListIterator<InfoBarEntry> it(m_infoBarEntries);
+    while (it.hasNext())
+        if (it.next().id == id)
+            return true;
+
+    return false;
+}
+
 void InfoBar::clear()
 {
     if (!m_infoBarEntries.isEmpty()) {

src/plugins/coreplugin/infobar.h

@@ -75,6 +75,7 @@ class CORE_EXPORT InfoBar : public QObject
 public:
     void addInfo(const InfoBarEntry &info);
     void removeInfo(const QString &id);
+    bool containsInfo(const QString &id) const;
     void clear();
 
 signals:

src/plugins/find/searchresultwidget.cpp

@@ -463,7 +463,7 @@ void SearchResultWidget::searchAgain()
 
 bool SearchResultWidget::showWarningMessage() const
 {
-    if (m_dontAskAgainGroup.isEmpty())
+    if (m_dontAskAgainGroup.isEmpty() || m_infoBar.containsInfo(QLatin1String(UNDO_WARNING_ID)))
         return false;
     // read settings
     QSettings *settings = Core::ICore::settings();