Add isEmpty method. We don't want to rely on toPlainText().isEmpty()

(cherry picked from commit a9361d56)

src/texteditor/plaintexteditor/plaintexteditorwidget.cpp

@@ -85,6 +85,12 @@ void PlainTextEditorWidget::setPlainText(const QString &text)
     d->mEditor->setPlainText(text);
 }
 
+
+bool PlainTextEditorWidget::isEmpty() const
+{
+    return d->mEditor->document()->isEmpty();
+}
+
 QString PlainTextEditorWidget::toPlainText() const
 {
     return d->mEditor->toPlainText();

src/texteditor/plaintexteditor/plaintexteditorwidget.h

@@ -47,6 +47,7 @@ public:
     void clear();
     void setSpellCheckingConfigFileName(const QString &_fileName);
 
+    bool isEmpty() const;
 private Q_SLOTS:
     void slotFind();
     void slotReplace();

src/texteditor/richtexteditor/richtexteditorwidget.cpp

@@ -106,6 +106,11 @@ void RichTextEditorWidget::setPlainText(const QString &text)
     d->mEditor->setPlainText(text);
 }
 
+bool RichTextEditorWidget::isEmpty() const
+{
+    return d->mEditor->document()->isEmpty();
+}
+
 QString RichTextEditorWidget::toPlainText() const
 {
     return d->mEditor->toPlainText();

src/texteditor/richtexteditor/richtexteditorwidget.h

@@ -55,6 +55,7 @@ public:
 
     void setSpellCheckingConfigFileName(const QString &_fileName);
 
+    bool isEmpty() const;
 public Q_SLOTS:
     void slotFindNext();
     void slotFind();