Add method for default text encoding to editor manager.

Moving the logic out of BaseTextDocument for use at other places.

src/plugins/texteditor/basetextdocument.cpp

@@ -132,12 +132,7 @@ BaseTextDocument::BaseTextDocument()
     m_lineTerminatorMode = NativeLineTerminator;
     m_fileIsReadOnly = false;
     m_isBinaryData = false;
-    m_codec = QTextCodec::codecForLocale();
-    QSettings *settings = Core::ICore::instance()->settings();
-    if (QTextCodec *candidate = QTextCodec::codecForName(
-            settings->value(QLatin1String("General/DefaultFileEncoding")).toByteArray()))
-        m_codec = candidate;
-
+    m_codec = Core::EditorManager::instance()->defaultTextEncoding();
     m_hasDecodingError = false;
 }