diff --git a/gfx/ipc/GfxMessageUtils.h b/gfx/ipc/GfxMessageUtils.h
index b375300da7b7..e4bc6162fc4b 100644
--- a/gfx/ipc/GfxMessageUtils.h
+++ b/gfx/ipc/GfxMessageUtils.h
@@ -393,7 +393,7 @@ template<class Units>
 struct ParamTraits<mozilla::gfx::IntRegionTyped<Units>>
   : RegionParamTraits<mozilla::gfx::IntRegionTyped<Units>,
                       mozilla::gfx::IntRectTyped<Units>,
-                      typename mozilla::gfx::IntRegionTyped<Units>::RectIterator>
+                      typename mozilla::gfx::IntRegionTyped<Units>::OldRectIterator>
 {};
 
 template<>
diff --git a/gfx/layers/LayersLogging.h b/gfx/layers/LayersLogging.h
index bf177d3b40d7..6e95348e9185 100644
--- a/gfx/layers/LayersLogging.h
+++ b/gfx/layers/LayersLogging.h
@@ -102,7 +102,7 @@ AppendToString(std::stringstream& aStream, const mozilla::gfx::IntRegionTyped<un
 
   aStream << pfx;
 
-  typename RegionType::RectIterator it(r);
+  typename RegionType::OldRectIterator it(r);
   aStream << "< ";
   while (const typename RegionType::RectType* sr = it.Next()) {
     AppendToString(aStream, *sr);
diff --git a/gfx/layers/basic/BasicCompositor.cpp b/gfx/layers/basic/BasicCompositor.cpp
index a3a12c3e92e6..d7bfb4e1075b 100644
--- a/gfx/layers/basic/BasicCompositor.cpp
+++ b/gfx/layers/basic/BasicCompositor.cpp
@@ -626,7 +626,7 @@ BasicCompositor::EndFrame()
   // The source DrawTarget is clipped to the invalidation region, so we have
   // to copy the individual rectangles in the region or else we'll draw blank
   // pixels.
-  LayoutDeviceIntRegion::RectIterator iter(mInvalidRegion);
+  LayoutDeviceIntRegion::OldRectIterator iter(mInvalidRegion);
   for (const LayoutDeviceIntRect *r = iter.Next(); r; r = iter.Next()) {
     dest->CopySurface(source,
                       IntRect(r->x - mInvalidRect.x, r->y - mInvalidRect.y, r->width, r->height),
diff --git a/gfx/layers/ipc/CompositorChild.cpp b/gfx/layers/ipc/CompositorChild.cpp
index b7aedf973bbd..61a4307d097b 100644
--- a/gfx/layers/ipc/CompositorChild.cpp
+++ b/gfx/layers/ipc/CompositorChild.cpp
@@ -234,7 +234,7 @@ static void CalculatePluginClip(const LayoutDeviceIntRect& aBounds,
   }
   // shift to plugin widget origin
   contentVisibleRegion.MoveBy(-aBounds.x, -aBounds.y);
-  LayoutDeviceIntRegion::RectIterator iter(contentVisibleRegion);
+  LayoutDeviceIntRegion::OldRectIterator iter(contentVisibleRegion);
   for (const LayoutDeviceIntRect* rgnRect = iter.Next(); rgnRect; rgnRect = iter.Next()) {
     aResult.AppendElement(*rgnRect);
     aVisibleBounds.UnionRect(aVisibleBounds, *rgnRect);
diff --git a/gfx/src/nsRegion.h b/gfx/src/nsRegion.h
index 952496ba9047..a809307f1f1a 100644
--- a/gfx/src/nsRegion.h
+++ b/gfx/src/nsRegion.h
@@ -351,6 +351,45 @@ public:
   void VisitEdges(visitFn, void *closure);
 
   nsCString ToString() const;
+
+  class RectIterator
+  {
+    int mCurrent;               // Index of the current entry
+    int mLimit;                 // Index one past the final entry.
+    mutable nsRect mTmp;        // The most recently gotten rectangle.
+    pixman_box32_t *mBoxes;
+
+  public:
+    explicit RectIterator(const nsRegion& aRegion)
+    {
+      mCurrent = 0;
+      mBoxes = pixman_region32_rectangles(aRegion.Impl(), &mLimit);
+      // Work around pixman bug. Sometimes pixman creates regions with 1 rect
+      // that's empty.
+      if (mLimit == 1 && nsRegion::BoxToRect(mBoxes[0]).IsEmpty()) {
+        mLimit = 0;
+      }
+    }
+
+    bool Done() const { return mCurrent == mLimit; }
+
+    const nsRect& Get() const
+    {
+      MOZ_ASSERT(!Done());
+      mTmp = nsRegion::BoxToRect(mBoxes[mCurrent]);
+      NS_ASSERTION(!mTmp.IsEmpty(), "Shouldn't return empty rect");
+      return mTmp;
+    }
+
+    void Next()
+    {
+      MOZ_ASSERT(!Done());
+      mCurrent++;
+    }
+  };
+
+  RectIterator RectIter() const { return RectIterator(*this); }
+
 private:
   pixman_region32_t mImpl;
 
@@ -701,7 +740,7 @@ public:
   nsRegion ToAppUnits (nscoord aAppUnitsPerPixel) const
   {
     nsRegion result;
-    RectIterator rgnIter(*this);
+    OldRectIterator rgnIter(*this);
     const Rect* currentRect;
     while ((currentRect = rgnIter.Next())) {
       nsRect appRect = ::ToAppUnits(*currentRect, aAppUnitsPerPixel);
@@ -768,13 +807,14 @@ public:
 
   nsCString ToString() const { return mImpl.ToString(); }
 
-  class RectIterator
+  // XXX: this is going away soon in favour of RectIterator
+  class OldRectIterator
   {
     nsRegionRectIterator mImpl;
     Rect mTmp;
 
   public:
-    explicit RectIterator (const BaseIntRegion& aRegion) : mImpl (aRegion.mImpl) {}
+    explicit OldRectIterator (const BaseIntRegion& aRegion) : mImpl (aRegion.mImpl) {}
 
     const Rect* Next ()
     {
@@ -800,6 +840,29 @@ public:
     }
   };
 
+  class RectIterator
+  {
+    nsRegion::RectIterator mImpl; // The underlying iterator.
+    mutable Rect mTmp;            // The most recently gotten rectangle.
+
+  public:
+    explicit RectIterator(const BaseIntRegion& aRegion)
+      : mImpl(aRegion.mImpl)
+    {}
+
+    bool Done() const { return mImpl.Done(); }
+
+    const Rect& Get() const
+    {
+      mTmp = FromRect(mImpl.Get());
+      return mTmp;
+    }
+
+    void Next() { mImpl.Next(); }
+  };
+
+  RectIterator RectIter() const { return RectIterator(*this); }
+
 protected:
   // Expose enough to derived classes from them to define conversions
   // between different types of BaseIntRegions.
@@ -875,6 +938,6 @@ private:
 } // namespace mozilla
 
 typedef mozilla::gfx::IntRegion nsIntRegion;
-typedef nsIntRegion::RectIterator nsIntRegionRectIterator;
+typedef nsIntRegion::OldRectIterator nsIntRegionRectIterator;
 
 #endif
diff --git a/widget/PuppetWidget.cpp b/widget/PuppetWidget.cpp
index ce7c7af6cfb5..bcc72f25f47b 100644
--- a/widget/PuppetWidget.cpp
+++ b/widget/PuppetWidget.cpp
@@ -32,7 +32,7 @@ using namespace mozilla::widget;
 static void
 InvalidateRegion(nsIWidget* aWidget, const LayoutDeviceIntRegion& aRegion)
 {
-  LayoutDeviceIntRegion::RectIterator it(aRegion);
+  LayoutDeviceIntRegion::OldRectIterator it(aRegion);
   while(const LayoutDeviceIntRect* r = it.Next()) {
     aWidget->Invalidate(*r);
   }
diff --git a/widget/cocoa/VibrancyManager.mm b/widget/cocoa/VibrancyManager.mm
index 26f9670b1fa1..411554e9b150 100644
--- a/widget/cocoa/VibrancyManager.mm
+++ b/widget/cocoa/VibrancyManager.mm
@@ -28,7 +28,7 @@ VibrancyManager::UpdateVibrantRegion(VibrancyType aType,
   vr.effectViews.SwapElements(viewsToRecycle);
   // vr.effectViews is now empty.
 
-  LayoutDeviceIntRegion::RectIterator iter(aRegion);
+  LayoutDeviceIntRegion::OldRectIterator iter(aRegion);
   const LayoutDeviceIntRect* iterRect = nullptr;
   for (size_t i = 0; (iterRect = iter.Next()) || i < viewsToRecycle.Length(); ++i) {
     if (iterRect) {
@@ -71,7 +71,7 @@ VibrancyManager::ClearVibrantRegion(const VibrantRegion& aVibrantRegion) const
 {
   [[NSColor clearColor] set];
 
-  LayoutDeviceIntRegion::RectIterator iter(aVibrantRegion.region);
+  LayoutDeviceIntRegion::OldRectIterator iter(aVibrantRegion.region);
   while (const LayoutDeviceIntRect* rect = iter.Next()) {
     NSRectFill(mCoordinateConverter.DevPixelsToCocoaPoints(*rect));
   }
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 8fba8c8c06b4..85d9a26cfa4e 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -3753,7 +3753,7 @@ NSEvent* gLastDragMouseDownEvent = nil;
   RefPtr<gfxContext> targetContext = new gfxContext(dt);
 
   // Set up the clip region.
-  LayoutDeviceIntRegion::RectIterator iter(region);
+  LayoutDeviceIntRegion::OldRectIterator iter(region);
   targetContext->NewPath();
   for (;;) {
     const LayoutDeviceIntRect* r = iter.Next();
@@ -4632,7 +4632,7 @@ NewCGSRegionFromRegion(const LayoutDeviceIntRegion& aRegion,
                        CGRect (^aRectConverter)(const LayoutDeviceIntRect&))
 {
   nsTArray<CGRect> rects;
-  LayoutDeviceIntRegion::RectIterator iter(aRegion);
+  LayoutDeviceIntRegion::OldRectIterator iter(aRegion);
   for (;;) {
     const LayoutDeviceIntRect* r = iter.Next();
     if (!r) {
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index c3497c4ee5d3..54cd58c0606f 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -758,7 +758,7 @@ nsBaseWidget::ArrayFromRegion(const LayoutDeviceIntRegion& aRegion,
                               nsTArray<LayoutDeviceIntRect>& aRects)
 {
   const LayoutDeviceIntRect* r;
-  for (LayoutDeviceIntRegion::RectIterator iter(aRegion); (r = iter.Next()); ) {
+  for (LayoutDeviceIntRegion::OldRectIterator iter(aRegion); (r = iter.Next()); ) {
     aRects.AppendElement(*r);
   }
 }
diff --git a/widget/nsShmImage.cpp b/widget/nsShmImage.cpp
index 82a28eeb18b1..784f3dc758a6 100644
--- a/widget/nsShmImage.cpp
+++ b/widget/nsShmImage.cpp
@@ -142,7 +142,7 @@ nsShmImage::Put(Display* aDisplay, Drawable aWindow,
     LayoutDeviceIntRegion bounded;
     bounded.And(aRegion,
                 LayoutDeviceIntRect(0, 0, mImage->width, mImage->height));
-    LayoutDeviceIntRegion::RectIterator iter(bounded);
+    LayoutDeviceIntRegion::OldRectIterator iter(bounded);
     for (const LayoutDeviceIntRect *r = iter.Next(); r; r = iter.Next()) {
         XShmPutImage(aDisplay, aWindow, gc, mImage,
                      r->x, r->y,
diff --git a/widget/uikit/nsWindow.mm b/widget/uikit/nsWindow.mm
index 4e80ec2e2b4b..ff8d75929f80 100644
--- a/widget/uikit/nsWindow.mm
+++ b/widget/uikit/nsWindow.mm
@@ -377,7 +377,7 @@ private:
   }
 
   // Set up the clip region.
-  LayoutDeviceIntRegion::RectIterator iter(region);
+  LayoutDeviceIntRegion::OldRectIterator iter(region);
   targetContext->NewPath();
   for (;;) {
     const LayoutDeviceIntRect* r = iter.Next();