--- a/dom/html/nsTextEditorState.cpp
+++ b/dom/html/nsTextEditorState.cpp
@@ -2538,17 +2538,17 @@ nsTextEditorState::SetValue(const nsAStr
 }
 
 bool
 nsTextEditorState::HasNonEmptyValue()
 {
   if (mTextEditor && mBoundFrame && mEditorInitialized &&
       !mIsCommittingComposition) {
     bool empty;
-    nsresult rv = mTextEditor->DocumentIsEmpty(&empty);
+    nsresult rv = mTextEditor->IsEmpty(&empty);
     if (NS_SUCCEEDED(rv)) {
       return !empty;
     }
   }
 
   nsAutoString value;
   GetValue(value, true);
   return !value.IsEmpty();

--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -995,23 +995,17 @@ EditorBase::SetShouldTxnSetSelection(boo
 {
   mShouldTxnSetSelection = aShould;
   return NS_OK;
 }
 
 NS_IMETHODIMP
 EditorBase::GetDocumentIsEmpty(bool* aDocumentIsEmpty)
 {
-  *aDocumentIsEmpty = true;
-
-  dom::Element* root = GetRoot();
-  NS_ENSURE_TRUE(root, NS_ERROR_NULL_POINTER);
-
-  *aDocumentIsEmpty = !root->HasChildren();
-  return NS_OK;
+  return NS_ERROR_NOT_IMPLEMENTED;
 }
 
 // XXX: The rule system should tell us which node to select all on (ie, the
 //      root, or the body)
 NS_IMETHODIMP
 EditorBase::SelectAll()
 {
   // XXX Why doesn't this check if the document is alive?

--- a/editor/libeditor/TextEditRules.cpp
+++ b/editor/libeditor/TextEditRules.cpp
@@ -392,17 +392,17 @@ TextEditRules::DidDoAction(Selection* aS
       return NS_OK;
   }
 }
 
 bool
 TextEditRules::DocumentIsEmpty()
 {
   bool retVal = false;
-  if (!mTextEditor || NS_FAILED(mTextEditor->DocumentIsEmpty(&retVal))) {
+  if (!mTextEditor || NS_FAILED(mTextEditor->IsEmpty(&retVal))) {
     retVal = true;
   }
 
   return retVal;
 }
 
 nsresult
 TextEditRules::WillInsert(bool* aCancel)

--- a/editor/libeditor/TextEditor.cpp
+++ b/editor/libeditor/TextEditor.cpp
@@ -1312,50 +1312,56 @@ TextEditor::OnCompositionEnd(WidgetCompo
 already_AddRefed<nsIContent>
 TextEditor::GetInputEventTargetContent()
 {
   nsCOMPtr<nsIContent> target = do_QueryInterface(mEventTarget);
   return target.forget();
 }
 
 nsresult
-TextEditor::DocumentIsEmpty(bool* aIsEmpty)
+TextEditor::IsEmpty(bool* aIsEmpty) const
 {
-  NS_ENSURE_TRUE(mRules, NS_ERROR_NOT_INITIALIZED);
+  if (NS_WARN_IF(!mRules)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  *aIsEmpty = true;
 
   if (mRules->HasBogusNode()) {
-    *aIsEmpty = true;
     return NS_OK;
   }
 
-  // Even if there is no bogus node, we should be detected as empty document
+  // Even if there is no bogus node, we should be detected as empty editor
   // if all the children are text nodes and these have no content.
   Element* rootElement = GetRoot();
   if (!rootElement) {
-    *aIsEmpty = true;
+    // XXX Why don't we return an error in such case??
     return NS_OK;
   }
 
   for (nsIContent* child = rootElement->GetFirstChild();
        child; child = child->GetNextSibling()) {
     if (!EditorBase::IsTextNode(child) ||
         static_cast<nsTextNode*>(child)->TextDataLength()) {
       *aIsEmpty = false;
       return NS_OK;
     }
   }
 
-  *aIsEmpty = true;
   return NS_OK;
 }
 
 NS_IMETHODIMP
 TextEditor::GetDocumentIsEmpty(bool* aDocumentIsEmpty)
 {
-  return DocumentIsEmpty(aDocumentIsEmpty);
+  nsresult rv = IsEmpty(aDocumentIsEmpty);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  return NS_OK;
 }
 
 NS_IMETHODIMP
 TextEditor::GetTextLength(int32_t* aCount)
 {
   NS_ASSERTION(aCount, "null pointer");
 
   // initialize out params

--- a/editor/libeditor/TextEditor.h
+++ b/editor/libeditor/TextEditor.h
@@ -93,17 +93,30 @@ public:
     */
   virtual bool CanPasteTransferable(nsITransferable* aTransferable);
 
   // Overrides of EditorBase
   virtual nsresult Init(nsIDocument& aDoc, Element* aRoot,
                         nsISelectionController* aSelCon, uint32_t aFlags,
                         const nsAString& aValue) override;
 
-  nsresult DocumentIsEmpty(bool* aIsEmpty);
+  /**
+   * IsEmpty() checks whether the editor is empty.  If editor has only bogus
+   * node, returns true.  If editor's root element has non-empty text nodes or
+   * other nodes like <br>, returns false.
+   */
+  nsresult IsEmpty(bool* aIsEmpty) const;
+  bool IsEmpty() const
+  {
+    bool isEmpty = false;
+    nsresult rv = IsEmpty(&isEmpty);
+    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+      "Checking whether the editor is empty failed");
+    return NS_SUCCEEDED(rv) && isEmpty;
+  }
 
   virtual nsresult HandleKeyPressEvent(
                      WidgetKeyboardEvent* aKeyboardEvent) override;
 
   virtual dom::EventTarget* GetDOMEventTarget() override;
 
   /**
    * InsertTextAsAction() inserts aStringToInsert at selection.