Remove a couple of QTextStream usages

Don't use QTextStream to write a QString to a file in UTF-8.
This can be done more easily, by directly converting the
QString to utf-8 and calling write on the io device.

Change-Id: I4b617b342ab339affb396ed49c5a920985d1ddfd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

examples/widgets/tools/codecs/mainwindow.cpp

@@ -122,9 +122,9 @@ void MainWindow::save()
         return;
     }
 
-    QTextStream out(&file);
-    out.setCodec(codecName.constData());
-    out << textEdit->toPlainText();
+    QTextCodec *codec = QTextCodec::codecForName(codecName.constData());
+    QByteArray text = codec->fromUnicode(textEdit->toPlainText());
+    file.write(text);
 }
 
 void MainWindow::about()

src/gui/doc/snippets/textdocument-blocks/mainwindow.cpp

@@ -154,10 +154,7 @@ bool MainWindow::writeXml(const QString &fileName)
     QFile file(fileName);
 
     if (file.open(QFile::WriteOnly)) {
-        QTextStream textStream(&file);
-        textStream.setCodec(QTextCodec::codecForName("UTF-8"));
-
-        textStream << domDocument->toString(1).toUtf8();
+        file.write(domDocument->toString(1).toUtf8());
         file.close();
         return true;
     }

src/gui/doc/snippets/textdocument-frames/mainwindow.cpp

@@ -159,10 +159,7 @@ bool MainWindow::writeXml(const QString &fileName)
     QFile file(fileName);
 
     if (file.open(QFile::WriteOnly)) {
-        QTextStream textStream(&file);
-        textStream.setCodec(QTextCodec::codecForName("UTF-8"));
-
-        textStream << domDocument->toString(1).toUtf8();
+        file.write(domDocument->toString(1).toUtf8());
         file.close();
         return true;
     }

src/gui/doc/snippets/textdocument-tables/mainwindow.cpp

@@ -202,10 +202,7 @@ bool MainWindow::writeXml(const QString &fileName)
     QFile file(fileName);
 
     if (file.open(QFile::WriteOnly)) {
-        QTextStream textStream(&file);
-        textStream.setCodec(QTextCodec::codecForName("UTF-8"));
-
-        textStream << domDocument->toString(1).toUtf8();
+        file.write(domDocument->toString(1).toUtf8());
         file.close();
         return true;
     }

src/gui/text/qtextdocumentwriter.cpp

@@ -286,11 +286,7 @@ bool QTextDocumentWriter::write(const QTextDocument *document)
             qWarning("QTextDocumentWriter::write: the device cannot be opened for writing");
             return false;
         }
-        QTextStream ts(d->device);
-#if QT_CONFIG(textcodec)
-        ts.setCodec("utf-8");
-#endif
-        ts << document->toPlainText();
+        d->device->write(document->toPlainText().toUtf8());
         d->device->close();
         return true;
     }