diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index 718a532d6461..73d86550e140 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -24,7 +24,6 @@
 #include "nsIObjectLoadingContent.h"
 #include "nsFrame.h"
 #include "mozilla/layers/ShadowLayers.h"
-#include "mozilla/layers/APZCCallbackHelper.h"
 #include "ClientLayerManager.h"
 #include "nsQueryObject.h"
 #ifdef MOZ_FMP4
@@ -2456,35 +2455,6 @@ nsDOMWindowUtils::SetAsyncScrollOffset(nsIDOMNode* aNode,
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsDOMWindowUtils::FlushApzRepaints(bool* aOutResult)
-{
-  nsIWidget* widget = GetWidget();
-  if (!widget) {
-    *aOutResult = false;
-    return NS_OK;
-  }
-  // If APZ is not enabled, this function is a no-op. After bug 1162064 this
-  // should be a widget->IsAsyncPanZoomEnabled() check.
-  if (!gfxPrefs::AsyncPanZoomEnabled()) {
-    *aOutResult = false;
-    return NS_OK;
-  }
-  LayerManager* manager = widget->GetLayerManager();
-  if (!manager) {
-    *aOutResult = false;
-    return NS_OK;
-  }
-  ShadowLayerForwarder* forwarder = manager->AsShadowForwarder();
-  if (!forwarder || !forwarder->HasShadowManager()) {
-    *aOutResult = false;
-    return NS_OK;
-  }
-  forwarder->GetShadowManager()->SendFlushApzRepaints();
-  *aOutResult = true;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsDOMWindowUtils::ComputeAnimationDistance(nsIDOMElement* aElement,
                                            const nsAString& aProperty,
diff --git a/dom/interfaces/base/nsIDOMWindowUtils.idl b/dom/interfaces/base/nsIDOMWindowUtils.idl
index 1edb636170fa..72602da9f868 100644
--- a/dom/interfaces/base/nsIDOMWindowUtils.idl
+++ b/dom/interfaces/base/nsIDOMWindowUtils.idl
@@ -49,7 +49,7 @@ interface nsIJSRAIIHelper;
 interface nsIContentPermissionRequest;
 interface nsIObserver;
 
-[scriptable, uuid(663e4d9a-c963-4949-b68e-3a6f71c0414f)]
+[scriptable, uuid(0ce789cc-3fb6-48b8-a58e-32deefc337b4)]
 interface nsIDOMWindowUtils : nsISupports {
 
   /**
@@ -1428,16 +1428,6 @@ interface nsIDOMWindowUtils : nsISupports {
    */
   void setAsyncScrollOffset(in nsIDOMNode aNode, in int32_t aX, in int32_t aY);
 
-  /**
-   * Do a round-trip to the compositor to ensure any pending APZ repaint requests
-   * get flushed to the main thread. If the function returns true, the flush was
-   * triggered and an "apz-repaints-flushed" notification will be dispatched via
-   * the observer service once the flush is complete. If the function returns
-   * false, an error occurred or a flush is not needed, and the notification
-   * will not fire. This is intended to be used by test code only!
-   */
-  bool flushApzRepaints();
-
   /**
    * Method for testing StyleAnimationValue::ComputeDistance.
    *
diff --git a/dom/ipc/PBrowser.ipdl b/dom/ipc/PBrowser.ipdl
index 4ad50026973f..29cb07c5a22b 100644
--- a/dom/ipc/PBrowser.ipdl
+++ b/dom/ipc/PBrowser.ipdl
@@ -589,7 +589,6 @@ child:
     HandleSingleTap(CSSPoint aPoint, Modifiers aModifiers, ScrollableLayerGuid aGuid);
     HandleLongTap(CSSPoint point, Modifiers aModifiers, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
     NotifyAPZStateChange(ViewID aViewId, APZStateChange aChange, int aArg);
-    NotifyFlushComplete();
 
 
     /**
diff --git a/dom/ipc/TabChild.cpp b/dom/ipc/TabChild.cpp
index eb2a3f9e762b..f6c37981eaf2 100644
--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -2138,13 +2138,6 @@ TabChild::RecvNotifyAPZStateChange(const ViewID& aViewId,
   return true;
 }
 
-bool
-TabChild::RecvNotifyFlushComplete()
-{
-  APZCCallbackHelper::NotifyFlushComplete();
-  return true;
-}
-
 bool
 TabChild::RecvActivate()
 {
diff --git a/dom/ipc/TabChild.h b/dom/ipc/TabChild.h
index 9039079715b6..a69368a24b25 100644
--- a/dom/ipc/TabChild.h
+++ b/dom/ipc/TabChild.h
@@ -342,7 +342,6 @@ public:
     virtual bool RecvNotifyAPZStateChange(const ViewID& aViewId,
                                           const APZStateChange& aChange,
                                           const int& aArg) override;
-    virtual bool RecvNotifyFlushComplete() override;
     virtual bool RecvActivate() override;
     virtual bool RecvDeactivate() override;
     virtual bool RecvMouseEvent(const nsString& aType,
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index c51b3f3cf5df..300f4c4471e0 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -1069,14 +1069,6 @@ TabParent::NotifyMouseScrollTestEvent(const ViewID& aScrollId, const nsString& a
   }
 }
 
-void
-TabParent::NotifyFlushComplete()
-{
-  if (!mIsDestroyed) {
-    unused << SendNotifyFlushComplete();
-  }
-}
-
 void
 TabParent::Activate()
 {
diff --git a/dom/ipc/TabParent.h b/dom/ipc/TabParent.h
index 0d36160e048c..81e0c7e1654b 100644
--- a/dom/ipc/TabParent.h
+++ b/dom/ipc/TabParent.h
@@ -274,7 +274,6 @@ public:
                               APZStateChange aChange,
                               int aArg);
     void NotifyMouseScrollTestEvent(const ViewID& aScrollId, const nsString& aEvent);
-    void NotifyFlushComplete();
     void Activate();
     void Deactivate();
 
diff --git a/gfx/layers/apz/public/GeckoContentController.h b/gfx/layers/apz/public/GeckoContentController.h
index 6673516c55ab..9756f8e95294 100644
--- a/gfx/layers/apz/public/GeckoContentController.h
+++ b/gfx/layers/apz/public/GeckoContentController.h
@@ -158,11 +158,6 @@ public:
   virtual void NotifyMozMouseScrollEvent(const FrameMetrics::ViewID& aScrollId, const nsString& aEvent)
   {}
 
-  /**
-   * Notify content that the repaint requests have been flushed.
-   */
-  virtual void NotifyFlushComplete() = 0;
-
   GeckoContentController() {}
   virtual void Destroy() {}
 
diff --git a/gfx/layers/apz/src/APZCTreeManager.cpp b/gfx/layers/apz/src/APZCTreeManager.cpp
index b510dcd5a08d..7e68e177a1b4 100644
--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -554,19 +554,6 @@ APZCTreeManager::UpdateHitTestingTree(TreeBuildingState& aState,
   return node;
 }
 
-void
-APZCTreeManager::FlushApzRepaints(uint64_t aLayersId)
-{
-  { // scope lock
-    MonitorAutoLock lock(mTreeLock);
-    FlushPendingRepaintRecursively(mRootNode, aLayersId);
-  }
-  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(aLayersId);
-  MOZ_ASSERT(state && state->mController);
-  NS_DispatchToMainThread(NS_NewRunnableMethod(
-    state->mController.get(), &GeckoContentController::NotifyFlushComplete));
-}
-
 nsEventStatus
 APZCTreeManager::ReceiveInputEvent(InputData& aEvent,
                                    ScrollableLayerGuid* aOutTargetGuid,
@@ -1084,23 +1071,6 @@ APZCTreeManager::FlushRepaintsRecursively(HitTestingTreeNode* aNode)
   }
 }
 
-void
-APZCTreeManager::FlushPendingRepaintRecursively(HitTestingTreeNode* aNode, uint64_t aLayersId)
-{
-  mTreeLock.AssertCurrentThreadOwns();
-
-  for (HitTestingTreeNode* node = aNode; node; node = node->GetPrevSibling()) {
-    if (node->IsPrimaryHolder()) {
-      AsyncPanZoomController* apzc = node->GetApzc();
-      MOZ_ASSERT(apzc);
-      if (apzc->GetGuid().mLayersId == aLayersId) {
-        apzc->FlushRepaintIfPending();
-      }
-    }
-    FlushPendingRepaintRecursively(node->GetLastChild(), aLayersId);
-  }
-}
-
 void
 APZCTreeManager::CancelAnimation(const ScrollableLayerGuid &aGuid)
 {
diff --git a/gfx/layers/apz/src/APZCTreeManager.h b/gfx/layers/apz/src/APZCTreeManager.h
index 3819f89ab8b6..5403e1fa4776 100644
--- a/gfx/layers/apz/src/APZCTreeManager.h
+++ b/gfx/layers/apz/src/APZCTreeManager.h
@@ -130,13 +130,6 @@ public:
                             uint64_t aOriginatingLayersId,
                             uint32_t aPaintSequenceNumber);
 
-  /**
-   * Walk the tree of APZCs and flushes the repaint requests for all the APZCS
-   * corresponding to the given layers id. Finally, sends a flush complete
-   * notification to the GeckoContentController for the layers id.
-   */
-  void FlushApzRepaints(uint64_t aLayersId);
-
   /**
    * General handler for incoming input events. Manipulates the frame metrics
    * based on what type of input it is. For example, a PinchGestureEvent will
@@ -437,7 +430,6 @@ private:
   void UpdateZoomConstraintsRecursively(HitTestingTreeNode* aNode,
                                         const ZoomConstraints& aConstraints);
   void FlushRepaintsRecursively(HitTestingTreeNode* aNode);
-  void FlushPendingRepaintRecursively(HitTestingTreeNode* aNode, uint64_t aLayersId);
 
   already_AddRefed<HitTestingTreeNode> RecycleOrCreateNode(TreeBuildingState& aState,
                                                            AsyncPanZoomController* aApzc);
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index 4e2d67fe9f24..9c1dc5601e7c 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -2446,13 +2446,6 @@ void AsyncPanZoomController::FlushRepaintForNewInputBlock() {
   UpdateSharedCompositorFrameMetrics();
 }
 
-void AsyncPanZoomController::FlushRepaintIfPending() {
-  // Just tell the paint throttler to send the pending repaint request if
-  // there is one.
-  ReentrantMonitorAutoEnter lock(mMonitor);
-  mPaintThrottler.TaskComplete(GetFrameTime());
-}
-
 bool AsyncPanZoomController::SnapBackIfOverscrolled() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   // It's possible that we're already in the middle of an overscroll
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.h b/gfx/layers/apz/src/AsyncPanZoomController.h
index cd64c5fa9621..ba756ef40a8c 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.h
+++ b/gfx/layers/apz/src/AsyncPanZoomController.h
@@ -183,11 +183,6 @@ public:
    */
   void NotifyLayersUpdated(const FrameMetrics& aLayerMetrics, bool aIsFirstPaint);
 
-  /**
-   * Flush any pending repaint request.
-   */
-  void FlushRepaintIfPending();
-
   /**
    * The platform implementation must set the compositor parent so that we can
    * request composites.
diff --git a/gfx/layers/apz/util/APZCCallbackHelper.cpp b/gfx/layers/apz/util/APZCCallbackHelper.cpp
index a7de7efd1be5..4db76d7f03df 100644
--- a/gfx/layers/apz/util/APZCCallbackHelper.cpp
+++ b/gfx/layers/apz/util/APZCCallbackHelper.cpp
@@ -710,15 +710,6 @@ APZCCallbackHelper::NotifyMozMouseScrollEvent(const FrameMetrics::ViewID& aScrol
     true, true);
 }
 
-void
-APZCCallbackHelper::NotifyFlushComplete()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
-  MOZ_ASSERT(observerService);
-  observerService->NotifyObservers(nullptr, "apz-repaints-flushed", nullptr);
-}
-
 }
 }
 
diff --git a/gfx/layers/apz/util/APZCCallbackHelper.h b/gfx/layers/apz/util/APZCCallbackHelper.h
index 171e0ea09c55..396d28f3ee2d 100644
--- a/gfx/layers/apz/util/APZCCallbackHelper.h
+++ b/gfx/layers/apz/util/APZCCallbackHelper.h
@@ -161,9 +161,6 @@ public:
 
     /* Notify content of a mouse scroll testing event. */
     static void NotifyMozMouseScrollEvent(const FrameMetrics::ViewID& aScrollId, const nsString& aEvent);
-
-    /* Notify content that the repaint flush is complete. */
-    static void NotifyFlushComplete();
 };
 
 }
diff --git a/gfx/layers/apz/util/ChromeProcessController.cpp b/gfx/layers/apz/util/ChromeProcessController.cpp
index 1f7d02d71b16..f60cae1f30a7 100644
--- a/gfx/layers/apz/util/ChromeProcessController.cpp
+++ b/gfx/layers/apz/util/ChromeProcessController.cpp
@@ -213,10 +213,3 @@ ChromeProcessController::NotifyMozMouseScrollEvent(const FrameMetrics::ViewID& a
 
   APZCCallbackHelper::NotifyMozMouseScrollEvent(aScrollId, aEvent);
 }
-
-void
-ChromeProcessController::NotifyFlushComplete()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  APZCCallbackHelper::NotifyFlushComplete();
-}
diff --git a/gfx/layers/apz/util/ChromeProcessController.h b/gfx/layers/apz/util/ChromeProcessController.h
index 0678afde0996..19e301d1f3e9 100644
--- a/gfx/layers/apz/util/ChromeProcessController.h
+++ b/gfx/layers/apz/util/ChromeProcessController.h
@@ -56,7 +56,6 @@ public:
                                     int aArg) override;
   virtual void NotifyMozMouseScrollEvent(const FrameMetrics::ViewID& aScrollId,
                                          const nsString& aEvent) override;
-  virtual void NotifyFlushComplete() override;
 private:
   nsCOMPtr<nsIWidget> mWidget;
   nsRefPtr<APZEventState> mAPZEventState;
diff --git a/gfx/layers/ipc/CompositorParent.cpp b/gfx/layers/ipc/CompositorParent.cpp
index 4a213bc8426f..787bd0f9cbea 100644
--- a/gfx/layers/ipc/CompositorParent.cpp
+++ b/gfx/layers/ipc/CompositorParent.cpp
@@ -1326,13 +1326,6 @@ CompositorParent::RecvRequestOverfill()
   return true;
 }
 
-void
-CompositorParent::FlushApzRepaints(const LayerTransactionParent* aLayerTree)
-{
-  MOZ_ASSERT(mApzcTreeManager);
-  mApzcTreeManager->FlushApzRepaints(aLayerTree->GetId());
-}
-
 void
 CompositorParent::GetAPZTestData(const LayerTransactionParent* aLayerTree,
                                  APZTestData* aOutData)
@@ -1741,7 +1734,6 @@ public:
   virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) override;
   virtual void ApplyAsyncProperties(LayerTransactionParent* aLayerTree)
                override;
-  virtual void FlushApzRepaints(const LayerTransactionParent* aLayerTree) override;
   virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                               APZTestData* aOutData) override;
   virtual void SetConfirmedTargetAPZC(const LayerTransactionParent* aLayerTree,
@@ -2154,21 +2146,6 @@ CrossProcessCompositorParent::ApplyAsyncProperties(
   state->mParent->ApplyAsyncProperties(aLayerTree);
 }
 
-void
-CrossProcessCompositorParent::FlushApzRepaints(const LayerTransactionParent* aLayerTree)
-{
-  uint64_t id = aLayerTree->GetId();
-  MOZ_ASSERT(id != 0);
-  const CompositorParent::LayerTreeState* state =
-    CompositorParent::GetIndirectShadowTree(id);
-  if (!state) {
-    return;
-  }
-
-  MOZ_ASSERT(state->mParent);
-  state->mParent->FlushApzRepaints(aLayerTree);
-}
-
 void
 CrossProcessCompositorParent::GetAPZTestData(const LayerTransactionParent* aLayerTree,
                                              APZTestData* aOutData)
diff --git a/gfx/layers/ipc/CompositorParent.h b/gfx/layers/ipc/CompositorParent.h
index e28db7ed3d8a..bedf15d0554c 100644
--- a/gfx/layers/ipc/CompositorParent.h
+++ b/gfx/layers/ipc/CompositorParent.h
@@ -268,7 +268,6 @@ public:
   virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) override;
   virtual void ApplyAsyncProperties(LayerTransactionParent* aLayerTree)
                override;
-  virtual void FlushApzRepaints(const LayerTransactionParent* aLayerTree) override;
   virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                               APZTestData* aOutData) override;
   virtual void SetConfirmedTargetAPZC(const LayerTransactionParent* aLayerTree,
diff --git a/gfx/layers/ipc/LayerTransactionParent.cpp b/gfx/layers/ipc/LayerTransactionParent.cpp
index f811b6d9df66..8fde530862fe 100644
--- a/gfx/layers/ipc/LayerTransactionParent.cpp
+++ b/gfx/layers/ipc/LayerTransactionParent.cpp
@@ -783,13 +783,6 @@ LayerTransactionParent::RecvSetAsyncScrollOffset(const FrameMetrics::ViewID& aSc
   return true;
 }
 
-bool
-LayerTransactionParent::RecvFlushApzRepaints()
-{
-  mShadowLayersManager->FlushApzRepaints(this);
-  return true;
-}
-
 bool
 LayerTransactionParent::RecvGetAPZTestData(APZTestData* aOutData)
 {
diff --git a/gfx/layers/ipc/LayerTransactionParent.h b/gfx/layers/ipc/LayerTransactionParent.h
index 79c1796fbe25..d63a3117d6b9 100644
--- a/gfx/layers/ipc/LayerTransactionParent.h
+++ b/gfx/layers/ipc/LayerTransactionParent.h
@@ -133,7 +133,6 @@ protected:
                                          override;
   virtual bool RecvSetAsyncScrollOffset(const FrameMetrics::ViewID& aId,
                                         const int32_t& aX, const int32_t& aY) override;
-  virtual bool RecvFlushApzRepaints() override;
   virtual bool RecvGetAPZTestData(APZTestData* aOutData) override;
   virtual bool RecvRequestProperty(const nsString& aProperty, float* aValue) override;
   virtual bool RecvSetConfirmedTargetAPZC(const uint64_t& aBlockId,
diff --git a/gfx/layers/ipc/PLayerTransaction.ipdl b/gfx/layers/ipc/PLayerTransaction.ipdl
index f160d15d0241..11a8ac65cf14 100644
--- a/gfx/layers/ipc/PLayerTransaction.ipdl
+++ b/gfx/layers/ipc/PLayerTransaction.ipdl
@@ -89,9 +89,6 @@ parent:
   // Useful for testing rendering of async scrolling.
   sync SetAsyncScrollOffset(ViewID id, int32_t x, int32_t y);
 
-  // Flush any pending APZ repaints to the main thread.
-  async FlushApzRepaints();
-
   // Drop any front buffers that might be retained on the compositor
   // side.
   async ClearCachedResources();
diff --git a/gfx/layers/ipc/ShadowLayersManager.h b/gfx/layers/ipc/ShadowLayersManager.h
index a17c5828824b..a11623e27c57 100644
--- a/gfx/layers/ipc/ShadowLayersManager.h
+++ b/gfx/layers/ipc/ShadowLayersManager.h
@@ -36,7 +36,6 @@ public:
                                    const TimeStamp& aTime) { return true; }
     virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) { }
     virtual void ApplyAsyncProperties(LayerTransactionParent* aLayerTree) = 0;
-    virtual void FlushApzRepaints(const LayerTransactionParent* aLayerTree) = 0;
     virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                                 APZTestData* aOutData) { }
     virtual void SetConfirmedTargetAPZC(const LayerTransactionParent* aLayerTree,
diff --git a/gfx/tests/gtest/TestAsyncPanZoomController.cpp b/gfx/tests/gtest/TestAsyncPanZoomController.cpp
index 1290ec30bff6..61005661135d 100644
--- a/gfx/tests/gtest/TestAsyncPanZoomController.cpp
+++ b/gfx/tests/gtest/TestAsyncPanZoomController.cpp
@@ -70,7 +70,6 @@ public:
   MOCK_METHOD3(SendAsyncScrollDOMEvent, void(bool aIsRoot, const CSSRect &aContentRect, const CSSSize &aScrollableSize));
   MOCK_METHOD2(PostDelayedTask, void(Task* aTask, int aDelayMs));
   MOCK_METHOD3(NotifyAPZStateChange, void(const ScrollableLayerGuid& aGuid, APZStateChange aChange, int aArg));
-  MOCK_METHOD0(NotifyFlushComplete, void());
 };
 
 class MockContentControllerDelayed : public MockContentController {
diff --git a/layout/ipc/RenderFrameParent.cpp b/layout/ipc/RenderFrameParent.cpp
index 78541cc790b2..52097f26fbf3 100644
--- a/layout/ipc/RenderFrameParent.cpp
+++ b/layout/ipc/RenderFrameParent.cpp
@@ -270,14 +270,6 @@ public:
     }
   }
 
-  void NotifyFlushComplete() override {
-    MOZ_ASSERT(NS_IsMainThread());
-    if (mRenderFrame) {
-      TabParent* browser = TabParent::GetFrom(mRenderFrame->Manager());
-      browser->NotifyFlushComplete();
-    }
-  }
-
   // Methods used by RenderFrameParent to set fields stored here.
 
   void SaveZoomConstraints(const ZoomConstraints& aConstraints)
diff --git a/layout/tools/reftest/reftest-content.js b/layout/tools/reftest/reftest-content.js
index 0cebf6a003fb..acf7cf3fff79 100644
--- a/layout/tools/reftest/reftest-content.js
+++ b/layout/tools/reftest/reftest-content.js
@@ -14,7 +14,6 @@ const XHTML_NS = "http://www.w3.org/1999/xhtml";
 const DEBUG_CONTRACTID = "@mozilla.org/xpcom/debug;1";
 const PRINTSETTINGS_CONTRACTID = "@mozilla.org/gfx/printsettings-service;1";
 const ENVIRONMENT_CONTRACTID = "@mozilla.org/process/environment;1";
-const NS_OBSERVER_SERVICE_CONTRACTID = "@mozilla.org/observer-service;1";
 
 // "<!--CLEAR-->"
 const BLANK_URL_FOR_CLEARING = "data:text/html;charset=UTF-8,%3C%21%2D%2DCLEAR%2D%2D%3E";
@@ -364,13 +363,10 @@ const STATE_WAITING_FOR_REFTEST_WAIT_REMOVAL = 1;
 // When spell checking is done on all spell-checked elements, we can move to the
 // next state.
 const STATE_WAITING_FOR_SPELL_CHECKS = 2;
-// When any pending compositor-side repaint requests have been flushed, we can
-// move to the next state.
-const STATE_WAITING_FOR_APZ_FLUSH = 3;
 // When all MozAfterPaint events and all explicit paint waits are flushed, we're
 // done and can move to the COMPLETED state.
-const STATE_WAITING_TO_FINISH = 4;
-const STATE_COMPLETED = 5;
+const STATE_WAITING_TO_FINISH = 3;
+const STATE_COMPLETED = 4;
 
 function FlushRendering() {
     var anyPendingPaintsGeneratedInDescendants = false;
@@ -536,31 +532,9 @@ function WaitForTestEnd(contentRootElement, inPrintMode, spellCheckedElements) {
                 return;
             }
 
-            state = STATE_WAITING_FOR_APZ_FLUSH;
-            LogInfo("MakeProgress: STATE_WAITING_FOR_APZ_FLUSH");
-            gFailureReason = "timed out waiting for APZ flush to complete";
-
-            var os = CC[NS_OBSERVER_SERVICE_CONTRACTID].getService(CI.nsIObserverService);
-            var flushWaiter = function(aSubject, aTopic, aData) {
-                if (aTopic) LogInfo("MakeProgress: apz-repaints-flushed fired");
-                os.removeObserver(flushWaiter, "apz-repaints-flushed");
-                state = STATE_WAITING_TO_FINISH;
-                MakeProgress();
-            };
-            os.addObserver(flushWaiter, "apz-repaints-flushed", false);
-
-            if (windowUtils().flushApzRepaints()) {
-                LogInfo("MakeProgress: done requesting APZ flush");
-            } else {
-                LogInfo("MakeProgress: APZ flush not required");
-                flushWaiter(null, null, null);
-            }
-            return;
-
-        case STATE_WAITING_FOR_APZ_FLUSH:
-            LogInfo("MakeProgress: STATE_WAITING_FOR_APZ_FLUSH");
-            // Nothing to do here; once we get the apz-repaints-flushed event
-            // we will go to STATE_WAITING_TO_FINISH
+            state = STATE_WAITING_TO_FINISH;
+            // Try next state
+            MakeProgress();
             return;
 
         case STATE_WAITING_TO_FINISH: