From: Simon Montagu <smontagu@smontagu.org>

diff --git a/layout/generic/nsIFrame.h b/layout/generic/nsIFrame.h
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -682,23 +682,60 @@ public:
    */
   nsRect GetRect() const { return mRect; }
   nsPoint GetPosition() const { return mRect.TopLeft(); }
   nsSize GetSize() const { return mRect.Size(); }
   nsRect GetRectRelativeToSelf() const {
     return nsRect(nsPoint(0, 0), mRect.Size());
   }
   /**
-   * Rect and position in logical coordinates in the frame's writing mode
+   * Dimensions and position in logical coordinates in the frame's writing mode
+   *  or another writing mode
    */
   mozilla::LogicalRect GetLogicalRect(nscoord aContainerWidth) const {
-    return mozilla::LogicalRect(GetWritingMode(), GetRect(), aContainerWidth);
+    return GetLogicalRect(GetWritingMode(), aContainerWidth);
   }
   mozilla::LogicalPoint GetLogicalPosition(nscoord aContainerWidth) const {
-    return GetLogicalRect(aContainerWidth).Origin(GetWritingMode());
+    return GetLogicalPosition(GetWritingMode(), aContainerWidth);
+  }
+  mozilla::LogicalSize GetLogicalSize() const {
+    return GetLogicalSize(GetWritingMode());
+  }
+  mozilla::LogicalRect GetLogicalRect(mozilla::WritingMode aWritingMode,
+                                      nscoord aContainerWidth) const {
+    return mozilla::LogicalRect(aWritingMode, GetRect(), aContainerWidth);
+  }
+  mozilla::LogicalPoint GetLogicalPosition(mozilla::WritingMode aWritingMode,
+                                           nscoord aContainerWidth) const {
+    return GetLogicalRect(aWritingMode, aContainerWidth).Origin(aWritingMode);
+  }
+  mozilla::LogicalSize GetLogicalSize(mozilla::WritingMode aWritingMode) const {
+    return mozilla::LogicalSize(aWritingMode, GetSize());
+  }
+  nscoord IStart(nscoord aContainerWidth) const {
+    return IStart(GetWritingMode(), aContainerWidth);
+  }
+  nscoord IStart(mozilla::WritingMode aWritingMode,
+                 nscoord aContainerWidth) const {
+    return GetLogicalPosition(aWritingMode, aContainerWidth).I(aWritingMode);
+  }
+  nscoord BStart(nscoord aContainerWidth) const {
+    return BStart(GetWritingMode(), aContainerWidth);
+  }
+  nscoord BStart(mozilla::WritingMode aWritingMode,
+                 nscoord aContainerWidth) const {
+    return GetLogicalPosition(aWritingMode, aContainerWidth).B(aWritingMode);
+  }
+  nscoord ISize() const { return ISize(GetWritingMode()); }
+  nscoord ISize(mozilla::WritingMode aWritingMode) const {
+    return GetLogicalSize(aWritingMode).ISize(aWritingMode);
+  }
+  nscoord BSize() const { return BSize(GetWritingMode()); }
+  nscoord BSize(mozilla::WritingMode aWritingMode) const {
+    return GetLogicalSize(aWritingMode).BSize(aWritingMode);
   }
 
   /**
    * When we change the size of the frame's border-box rect, we may need to
    * reset the overflow rect if it was previously stored as deltas.
    * (If it is currently a "large" overflow and could be re-packed as deltas,
    * we don't bother as the cost of the allocation has already been paid.)
    */
@@ -710,27 +747,26 @@ public:
       SetOverflowAreas(overflow);
     } else {
       mRect = aRect;
     }
   }
   /**
    * Set this frame's rect from a logical rect in its own writing direction
    */
-  void SetRectFromLogicalRect(const mozilla::LogicalRect& aRect,
-                              nscoord aContainerWidth) {
-    SetRectFromLogicalRect(GetWritingMode(), aRect, aContainerWidth);
+  void SetRect(const mozilla::LogicalRect& aRect, nscoord aContainerWidth) {
+    SetRect(GetWritingMode(), aRect, aContainerWidth);
   }
   /**
    * Set this frame's rect from a logical rect in a different writing direction
    * (GetPhysicalRect will assert if the writing mode doesn't match)
    */
-  void SetRectFromLogicalRect(mozilla::WritingMode aWritingMode,
-                              const mozilla::LogicalRect& aRect,
-                              nscoord aContainerWidth) {
+  void SetRect(mozilla::WritingMode aWritingMode,
+               const mozilla::LogicalRect& aRect,
+               nscoord aContainerWidth) {
     SetRect(aRect.GetPhysicalRect(aWritingMode, aContainerWidth));
   }
   void SetSize(const nsSize& aSize) {
     SetRect(nsRect(mRect.TopLeft(), aSize));
   }
   void SetPosition(const nsPoint& aPt) { mRect.MoveTo(aPt); }
 
   /**