--- a/layout/generic/nsCanvasFrame.h
+++ b/layout/generic/nsCanvasFrame.h
@@ -39,26 +39,19 @@ public:
 
   NS_DECL_QUERYFRAME_TARGET(nsCanvasFrame)
   NS_DECL_QUERYFRAME
   NS_DECL_FRAMEARENA_HELPERS
 
 
   virtual void DestroyFrom(nsIFrame* aDestructRoot) override;
 
-  virtual mozilla::WritingMode GetWritingMode() const override
+  mozilla::WritingMode GetWritingMode() const override
   {
-    nsIContent* rootElem = GetContent();
-    if (rootElem) {
-      nsIFrame* rootElemFrame = rootElem->GetPrimaryFrame();
-      if (rootElemFrame) {
-        return rootElemFrame->GetWritingMode();
-      }
-    }
-    return nsIFrame::GetWritingMode();
+    return nsFrame::GetWritingModeDeferringToRootElem();
   }
 
 #ifdef DEBUG
   virtual void SetInitialChildList(ChildListID     aListID,
                                    nsFrameList&    aChildList) override;
   virtual void AppendFrames(ChildListID     aListID,
                             nsFrameList&    aFrameList) override;
   virtual void InsertFrames(ChildListID     aListID,

--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -3015,16 +3015,29 @@ nsFrame::FireDOMEvent(const nsAString& a
   if (target) {
     RefPtr<AsyncEventDispatcher> asyncDispatcher =
       new AsyncEventDispatcher(target, aDOMEventName, true, false);
     DebugOnly<nsresult> rv = asyncDispatcher->PostDOMEvent();
     NS_ASSERTION(NS_SUCCEEDED(rv), "AsyncEventDispatcher failed to dispatch");
   }
 }
 
+WritingMode
+nsFrame::GetWritingModeDeferringToRootElem() const
+{
+  Element* rootElem = PresContext()->Document()->GetRootElement();
+  if (rootElem) {
+    nsIFrame* primaryFrame = rootElem->GetPrimaryFrame();
+    if (primaryFrame) {
+      return primaryFrame->GetWritingMode();
+    }
+  }
+  return nsIFrame::GetWritingMode();
+}
+
 nsresult
 nsFrame::HandleEvent(nsPresContext* aPresContext, 
                      WidgetGUIEvent* aEvent,
                      nsEventStatus* aEventStatus)
 {
 
   if (aEvent->mMessage == eMouseMove) {
     // XXX If the second argument of HandleDrag() is WidgetMouseEvent,

--- a/layout/generic/nsFrame.h
+++ b/layout/generic/nsFrame.h
@@ -683,16 +683,18 @@ protected:
   void GetBoxName(nsAutoString& aName) override;
 #endif
 
   nsBoxLayoutMetrics* BoxMetrics() const;
 
   // Fire DOM event. If no aContent argument use frame's mContent.
   void FireDOMEvent(const nsAString& aDOMEventName, nsIContent *aContent = nullptr);
 
+  mozilla::WritingMode GetWritingModeDeferringToRootElem() const;
+
 private:
   void BoxReflow(nsBoxLayoutState& aState,
                  nsPresContext*    aPresContext,
                  ReflowOutput&     aDesiredSize,
                  nsRenderingContext* aRenderingContext,
                  nscoord aX,
                  nscoord aY,
                  nscoord aWidth,

--- a/layout/generic/nsPageContentFrame.cpp
+++ b/layout/generic/nsPageContentFrame.cpp
@@ -106,17 +106,17 @@ nsPageContentFrame::Reflow(nsPresContext
   FinishAndStoreOverflow(&aDesiredSize);
 
   NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
 }
 
 nsIAtom*
 nsPageContentFrame::GetType() const
 {
-  return nsGkAtoms::pageContentFrame; 
+  return nsGkAtoms::pageContentFrame;
 }
 
 #ifdef DEBUG_FRAME_DUMP
 nsresult
 nsPageContentFrame::GetFrameName(nsAString& aResult) const
 {
   return MakeFrameName(NS_LITERAL_STRING("PageContent"), aResult);
 }

--- a/layout/generic/nsPageContentFrame.h
+++ b/layout/generic/nsPageContentFrame.h
@@ -38,17 +38,22 @@ public:
   virtual bool HasTransformGetter() const override { return true; }
 
   /**
    * Get the "type" of the frame
    *
    * @see nsGkAtoms::pageContentFrame
    */
   virtual nsIAtom* GetType() const override;
-  
+
+  mozilla::WritingMode GetWritingMode() const override
+  {
+    return nsFrame::GetWritingModeDeferringToRootElem();
+  }
+
 #ifdef DEBUG_FRAME_DUMP
   // Debugging
   virtual nsresult  GetFrameName(nsAString& aResult) const override;
 #endif
 
 protected:
   explicit nsPageContentFrame(nsStyleContext* aContext) : ViewportFrame(aContext) {}
 

--- a/layout/generic/nsPageFrame.h
+++ b/layout/generic/nsPageFrame.h
@@ -27,23 +27,28 @@ public:
                       ReflowOutput& aDesiredSize,
                       const ReflowInput& aMaxSize,
                       nsReflowStatus&      aStatus) override;
 
   virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                 const nsRect&           aDirtyRect,
                                 const nsDisplayListSet& aLists) override;
 
+  mozilla::WritingMode GetWritingMode() const override
+  {
+    return nsFrame::GetWritingModeDeferringToRootElem();
+  }
+
   /**
    * Get the "type" of the frame
    *
    * @see nsGkAtoms::pageFrame
    */
   virtual nsIAtom* GetType() const override;
-  
+
 #ifdef DEBUG_FRAME_DUMP
   virtual nsresult  GetFrameName(nsAString& aResult) const override;
 #endif
 
   //////////////////
   // For Printing
   //////////////////
 

--- a/layout/generic/nsSimplePageSequenceFrame.h
+++ b/layout/generic/nsSimplePageSequenceFrame.h
@@ -55,16 +55,21 @@ class nsSimplePageSequenceFrame : public
                                   public nsIPageSequenceFrame {
 public:
   friend nsSimplePageSequenceFrame* NS_NewSimplePageSequenceFrame(nsIPresShell* aPresShell,
                                                                   nsStyleContext* aContext);
 
   NS_DECL_QUERYFRAME
   NS_DECL_FRAMEARENA_HELPERS
 
+  mozilla::WritingMode GetWritingMode() const override
+  {
+    return nsFrame::GetWritingModeDeferringToRootElem();
+  }
+
   // nsIFrame
   void Reflow(nsPresContext* aPresContext,
               ReflowOutput& aDesiredSize,
               const ReflowInput& aMaxSize,
               nsReflowStatus& aStatus) override;
 
   void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                         const nsRect&           aDirtyRect,