Make sure bookmarks survive a document reload

While reloading a text document, the bookmarks got lost since their
associated QTextBlocks were deleted.

This patch makes sure that before reloading, the bookmarks are removed
non-persistently in the same way as when closing a document, and that
they are restored after the document was reloaded.

Currently, no effort is made to update the location of the bookmarks
based on the way the file changed.

Task-number: QTCREATORBUG-1281
Reviewed-by: dt

src/plugins/texteditor/basetextdocument.h

@@ -76,7 +76,7 @@ public:
     inline const StorageSettings &storageSettings() const { return m_storageSettings; }
     inline const TabSettings &tabSettings() const { return m_tabSettings; }
 
-    DocumentMarker *documentMarker() const {return m_documentMarker; }
+    DocumentMarker *documentMarker() const { return m_documentMarker; }
 
     //IFile
     virtual bool save(const QString &fileName = QString());
@@ -116,8 +116,6 @@ public:
 
 signals:
     void titleChanged(QString title);
-    void aboutToReload();
-    void reloaded();
 
 private:
     QString m_fileName;
@@ -150,6 +148,7 @@ private:
 
     void cleanWhitespace(QTextCursor& cursor, bool cleanIndentation, bool inEntireDocument);
     void ensureFinalNewLine(QTextCursor& cursor);
+    void documentClosing();
 };
 
 } // namespace TextEditor