Bug 1166147 - Part3: Override GetWritingMode() and make it more robustly defer to root element, to avoid truncating printed vertical-WM docs. r=dholbert

MozReview-Commit-ID: IYM3gzf1CpS

--HG--
extra : rebase_source : fa8afc85a6f3139c3c8f296ed3a469a87020a746

layout/generic/nsCanvasFrame.h

@@ -44,16 +44,9 @@ public:
 
   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

layout/generic/nsFrame.cpp

@@ -3020,6 +3020,19 @@ nsFrame::FireDOMEvent(const nsAString& aDOMEventName, nsIContent *aContent)
   }
 }
 
+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,

layout/generic/nsFrame.h

@@ -688,6 +688,8 @@ protected:
   // 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,

layout/generic/nsPageContentFrame.h

@@ -44,6 +44,11 @@ public:
    */
   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;

layout/generic/nsPageFrame.h

@@ -32,6 +32,11 @@ public:
                                 const nsRect&           aDirtyRect,
                                 const nsDisplayListSet& aLists) override;
 
+  mozilla::WritingMode GetWritingMode() const override
+  {
+    return nsFrame::GetWritingModeDeferringToRootElem();
+  }
+
   /**
    * Get the "type" of the frame
    *

layout/generic/nsSimplePageSequenceFrame.h

@@ -60,6 +60,11 @@ public:
   NS_DECL_QUERYFRAME
   NS_DECL_FRAMEARENA_HELPERS
 
+  mozilla::WritingMode GetWritingMode() const override
+  {
+    return nsFrame::GetWritingModeDeferringToRootElem();
+  }
+
   // nsIFrame
   void Reflow(nsPresContext* aPresContext,
               ReflowOutput& aDesiredSize,