--- a/gfx/layers/apz/src/FocusState.cpp
+++ b/gfx/layers/apz/src/FocusState.cpp
@@ -38,20 +38,20 @@ FocusState::ReceiveFocusChangingEvent()
   mLastAPZProcessedEvent += 1;
 }
 
 void
 FocusState::Update(uint64_t aRootLayerTreeId,
                    uint64_t aOriginatingLayersId,
                    const FocusTarget& aState)
 {
-  FS_LOG("Update with rlt=%" PRIu64 ", olt=%" PRIu64 ", ft=(%d, %" PRIu64 ")\n",
+  FS_LOG("Update with rlt=%" PRIu64 ", olt=%" PRIu64 ", ft=(%s, %" PRIu64 ")\n",
          aRootLayerTreeId,
          aOriginatingLayersId,
-         static_cast<int>(aState.mType),
+         aState.Type(),
          aState.mSequenceNumber);
 
   // Update the focus tree with the latest target
   mFocusTree[aOriginatingLayersId] = aState;
 
   // Reset our internal state so we can recalculate it
   mFocusHasKeyEventListeners = false;
   mFocusLayersId = aRootLayerTreeId;

--- a/gfx/layers/apz/src/FocusTarget.cpp
+++ b/gfx/layers/apz/src/FocusTarget.cpp
@@ -225,10 +225,25 @@ FocusTarget::FocusTarget(nsIPresShell* a
 bool
 FocusTarget::operator==(const FocusTarget& aRhs) const
 {
   return mSequenceNumber == aRhs.mSequenceNumber &&
          mFocusHasKeyEventListeners == aRhs.mFocusHasKeyEventListeners &&
          mData == aRhs.mData;
 }
 
+const char*
+FocusTarget::Type() const
+{
+  if (mData.is<RefLayerId>()) {
+    return "RefLayerId";
+  }
+  if (mData.is<ScrollTargets>()) {
+    return "ScrollTargets";
+  }
+  if (mData.is<NoFocusTarget>()) {
+    return "NoFocusTarget";
+  }
+  return "<unknown>";
+}
+
 } // namespace layers
 } // namespace mozilla

--- a/gfx/layers/apz/src/FocusTarget.h
+++ b/gfx/layers/apz/src/FocusTarget.h
@@ -54,16 +54,18 @@ public:
   /**
    * Construct a focus target for the specified top level PresShell
    */
   FocusTarget(nsIPresShell* aRootPresShell,
               uint64_t aFocusSequenceNumber);
 
   bool operator==(const FocusTarget& aRhs) const;
 
+  const char* Type() const;
+
 public:
   // The content sequence number recorded at the time of this class's creation
   uint64_t mSequenceNumber;
 
   // Whether there are keydown, keypress, or keyup event listeners
   // in the event target chain of the focused element
   bool mFocusHasKeyEventListeners;