--- a/dom/base/Selection.cpp
+++ b/dom/base/Selection.cpp
@@ -405,16 +405,73 @@ void Selection::SetCaretBidiLevel(const 
   }
   if (aCaretBidiLevel.IsNull()) {
     mFrameSelection->UndefineCaretBidiLevel();
   } else {
     mFrameSelection->SetCaretBidiLevel(aCaretBidiLevel.Value());
   }
 }
 
+/**
+ * Test whether the supplied range points to a single table element.
+ * Result is one of the TableSelection constants. "None" means
+ * a table element isn't selected.
+ */
+// TODO: Figure out TableSelection::Column and TableSelection::AllCells
+static nsresult GetTableSelectionType(nsRange* aRange,
+                                      TableSelection* aTableSelectionType) {
+  if (!aRange || !aTableSelectionType) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  *aTableSelectionType = TableSelection::None;
+
+  nsINode* startNode = aRange->GetStartContainer();
+  if (!startNode) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsINode* endNode = aRange->GetEndContainer();
+  if (!endNode) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Not a single selected node
+  if (startNode != endNode) {
+    return NS_OK;
+  }
+
+  nsIContent* child = aRange->GetChildAtStartOffset();
+
+  // Not a single selected node
+  if (!child || child->GetNextSibling() != aRange->GetChildAtEndOffset()) {
+    return NS_OK;
+  }
+
+  nsIContent* startContent = static_cast<nsIContent*>(startNode);
+  if (!(startNode->IsElement() && startContent->IsHTMLElement())) {
+    // Implies a check for being an element; if we ever make this work
+    // for non-HTML, need to keep checking for elements.
+    return NS_OK;
+  }
+
+  if (startContent->IsHTMLElement(nsGkAtoms::tr)) {
+    *aTableSelectionType = TableSelection::Cell;
+  } else  // check to see if we are selecting a table or row (column and all
+          // cells not done yet)
+  {
+    if (child->IsHTMLElement(nsGkAtoms::table))
+      *aTableSelectionType = TableSelection::Table;
+    else if (child->IsHTMLElement(nsGkAtoms::tr))
+      *aTableSelectionType = TableSelection::Row;
+  }
+
+  return NS_OK;
+}
+
 nsresult Selection::GetTableCellLocationFromRange(
     nsRange* aRange, TableSelection* aSelectionType, int32_t* aRow,
     int32_t* aCol) {
   if (!aRange || !aSelectionType || !aRow || !aCol)
     return NS_ERROR_NULL_POINTER;
 
   *aSelectionType = TableSelection::None;
   *aRow = 0;
@@ -488,63 +545,16 @@ nsresult Selection::MaybeAddTableCellRan
   // getTableCellLocation)
   if (mFrameSelection->mSelectingTableCellMode == TableSelection::None)
     mFrameSelection->mSelectingTableCellMode = tableMode;
 
   *aDidAddRange = true;
   return AddRangesForSelectableNodes(aRange, aOutIndex);
 }
 
-// TODO: Figure out TableSelection::Column and TableSelection::AllCells
-nsresult Selection::GetTableSelectionType(nsRange* aRange,
-                                          TableSelection* aTableSelectionType) {
-  if (!aRange || !aTableSelectionType) return NS_ERROR_NULL_POINTER;
-
-  *aTableSelectionType = TableSelection::None;
-
-  // Must have access to frame selection to get cell info
-  if (!mFrameSelection) return NS_OK;
-
-  nsINode* startNode = aRange->GetStartContainer();
-  if (!startNode) return NS_ERROR_FAILURE;
-
-  nsINode* endNode = aRange->GetEndContainer();
-  if (!endNode) return NS_ERROR_FAILURE;
-
-  // Not a single selected node
-  if (startNode != endNode) return NS_OK;
-
-  nsIContent* child = aRange->GetChildAtStartOffset();
-
-  // Not a single selected node
-  if (!child || child->GetNextSibling() != aRange->GetChildAtEndOffset()) {
-    return NS_OK;
-  }
-
-  nsIContent* startContent = static_cast<nsIContent*>(startNode);
-  if (!(startNode->IsElement() && startContent->IsHTMLElement())) {
-    // Implies a check for being an element; if we ever make this work
-    // for non-HTML, need to keep checking for elements.
-    return NS_OK;
-  }
-
-  if (startContent->IsHTMLElement(nsGkAtoms::tr)) {
-    *aTableSelectionType = TableSelection::Cell;
-  } else  // check to see if we are selecting a table or row (column and all
-          // cells not done yet)
-  {
-    if (child->IsHTMLElement(nsGkAtoms::table))
-      *aTableSelectionType = TableSelection::Table;
-    else if (child->IsHTMLElement(nsGkAtoms::tr))
-      *aTableSelectionType = TableSelection::Row;
-  }
-
-  return NS_OK;
-}
-
 Selection::Selection()
     : mCachedOffsetForFrame(nullptr),
       mDirection(eDirNext),
       mSelectionType(SelectionType::eNormal),
       mCustomColors(nullptr),
       mSelectionChangeBlockerCount(0),
       mUserInitiated(false),
       mCalledByJS(false),

--- a/dom/base/Selection.h
+++ b/dom/base/Selection.h
@@ -707,23 +707,16 @@ class Selection final : public nsSupport
                         bool aSelect);
 
   /**
    * SelectFramesInAllRanges() calls SelectFrames() for all current
    * ranges.
    */
   void SelectFramesInAllRanges(nsPresContext* aPresContext);
 
-  /**
-   * Test whether the supplied range points to a single table element.
-   * Result is one of the TableSelection constants. "None" means
-   * a table element isn't selected.
-   */
-  nsresult GetTableSelectionType(nsRange* aRange,
-                                 TableSelection* aTableSelectionType);
   MOZ_CAN_RUN_SCRIPT_BOUNDARY
   nsresult GetTableCellLocationFromRange(nsRange* aRange,
                                          TableSelection* aSelectionType,
                                          int32_t* aRow, int32_t* aCol);
 
   /**
    * @param aOutIndex points to the index of the range in mRanges. If
    *                  aDidAddRange is true, it is in [0, mRanges.Length()).