diff --git a/dom/ipc/TabChild.h b/dom/ipc/TabChild.h
index bc9e06d0fc1..25447e5836f 100644
--- a/dom/ipc/TabChild.h
+++ b/dom/ipc/TabChild.h
@@ -291,6 +291,8 @@ public:
     /** Return the DPI of the widget this TabChild draws to. */
     void GetDPI(float* aDPI);
 
+    gfxSize GetZoom() { return mLastMetrics.mZoom; }
+
     void SetBackgroundColor(const nscolor& aColor);
 
     void NotifyPainted();
diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index 99c747f5840..9ed6144798e 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -10,6 +10,11 @@
  * used during painting and hit testing
  */
 
+// include PBrowserChild explicitly because TabChild won't include it
+// because we're in layout :(
+#include "mozilla/dom/PBrowserChild.h"
+#include "mozilla/dom/TabChild.h"
+
 #include "mozilla/layers/PLayers.h"
 
 #include "nsDisplayList.h"
@@ -50,6 +55,7 @@
 using namespace mozilla;
 using namespace mozilla::css;
 using namespace mozilla::layers;
+using namespace mozilla::dom;
 typedef FrameMetrics::ViewID ViewID;
 
 static void AddTransformFunctions(nsCSSValueList* aList,
@@ -658,6 +664,9 @@ static void RecordFrameMetrics(nsIFrame* aForFrame,
   metrics.mScrollId = aScrollId;
 
   nsIPresShell* presShell = presContext->GetPresShell();
+  if (TabChild *tc = GetTabChildFrom(presShell)) {
+    metrics.mZoom = tc->GetZoom();
+  }
   metrics.mResolution = gfxSize(presShell->GetXResolution(), presShell->GetYResolution());
 
   metrics.mDevPixelsPerCSSPixel = auPerCSSPixel / auPerDevPixel;