--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -72,16 +72,17 @@
 #include "nsThreadUtils.h"              // for NS_IsMainThread
 #include "nsViewportInfo.h"             // for kViewportMinScale, kViewportMaxScale
 #include "prsystem.h"                   // for PR_GetPhysicalMemorySize
 #include "SharedMemoryBasic.h"          // for SharedMemoryBasic
 #include "ScrollSnap.h"                 // for ScrollSnapUtils
 #include "WheelScrollAnimation.h"
 #if defined(MOZ_WIDGET_ANDROID)
 #include "AndroidAPZ.h"
+#include "mozilla/layers/AndroidDynamicToolbarAnimator.h"
 #endif // defined(MOZ_WIDGET_ANDROID)
 
 #define ENABLE_APZC_LOGGING 0
 // #define ENABLE_APZC_LOGGING 1
 
 #if ENABLE_APZC_LOGGING
 #  define APZC_LOG(...) printf_stderr("APZC: " __VA_ARGS__)
 #  define APZC_LOG_FM(fm, prefix, ...) \
@@ -1184,22 +1185,16 @@ nsEventStatus AsyncPanZoomController::On
       break;
   }
 
   return nsEventStatus_eConsumeNoDefault;
 }
 
 nsEventStatus AsyncPanZoomController::OnTouchEnd(const MultiTouchInput& aEvent) {
   APZC_LOG("%p got a touch-end in state %d\n", this, mState);
-
-  RefPtr<GeckoContentController> controller = GetGeckoContentController();
-  if (controller) {
-    controller->SetScrollingRootContent(false);
-  }
-
   OnTouchEndOrCancel();
 
   // In case no touch behavior triggered previously we can avoid sending
   // scroll events or requesting content repaint. This condition is added
   // to make tests consistent - in case touch-action is NONE (and therefore
   // no pans/zooms can be performed) we expected neither scroll or repaint
   // events.
   if (mState != NOTHING) {
@@ -2394,22 +2389,23 @@ bool AsyncPanZoomController::AttemptScro
 
     if (xChanged || yChanged) {
       ScheduleComposite();
     }
 
     if (!IsZero(adjustedDisplacement)) {
       ScrollBy(adjustedDisplacement / mFrameMetrics.GetZoom());
       if (CancelableBlockState* block = GetCurrentInputBlock()) {
-        if (block->AsTouchBlock() && (block->GetScrolledApzc() != this)) {
-          RefPtr<GeckoContentController> controller = GetGeckoContentController();
-          if (controller) {
-            controller->SetScrollingRootContent(IsRootContent());
-          }
+#if defined(MOZ_WIDGET_ANDROID)
+        if (block->AsTouchBlock() && (block->GetScrolledApzc() != this) && IsRootContent()) {
+          AndroidDynamicToolbarAnimator* animator = GetApzcTreeManager()->GetAndroidDynamicToolbarAnimator();
+          MOZ_ASSERT(animator);
+          animator->SetScrollingRootContent();
         }
+#endif
         block->SetScrolledApzc(this);
       }
       ScheduleCompositeAndMaybeRepaint();
       UpdateSharedCompositorFrameMetrics();
     }
 
     // Adjust the start point to reflect the consumed portion of the scroll.
     aStartPoint = aEndPoint + overscroll;
@@ -3411,16 +3407,27 @@ void AsyncPanZoomController::NotifyLayer
   }
 
   bool smoothScrollRequested = aLayerMetrics.GetDoSmoothScroll()
        && (aLayerMetrics.GetScrollGeneration() != mFrameMetrics.GetScrollGeneration());
 
   // TODO if we're in a drag and scrollOffsetUpdated is set then we want to
   // ignore it
 
+#if defined(MOZ_WIDGET_ANDROID)
+  if (aLayerMetrics.IsRootContent()) {
+    AndroidDynamicToolbarAnimator* animator = GetApzcTreeManager()->GetAndroidDynamicToolbarAnimator();
+    MOZ_ASSERT(animator);
+    ScreenIntSize size = ScreenIntSize::Round(aLayerMetrics.GetRootCompositionSize() * aLayerMetrics.DisplayportPixelsPerCSSPixel());
+    if (animator->SetCompositionSize(size.width, size.height)) {
+      animator->UpdateRootFrameMetrics(aLayerMetrics);
+    }
+  }
+#endif
+
   if ((aIsFirstPaint && aThisLayerTreeUpdated) || isDefault) {
     // Initialize our internal state to something sane when the content
     // that was just painted is something we knew nothing about previously
     CancelAnimation();
 
     mScrollMetadata = aScrollMetadata;
     mExpectedGeckoMetrics = aLayerMetrics;
     ShareCompositorFrameMetrics();
@@ -3770,17 +3777,23 @@ void AsyncPanZoomController::DispatchSta
                                                              PanZoomState aNewState)
 {
   { // scope the lock
     ReentrantMonitorAutoEnter lock(mMonitor);
     if (mNotificationBlockers > 0) {
       return;
     }
   }
-
+#if defined(MOZ_WIDGET_ANDROID)
+  if ((aNewState == NOTHING) && mFrameMetrics.IsRootContent()) {
+    AndroidDynamicToolbarAnimator* animator = GetApzcTreeManager()->GetAndroidDynamicToolbarAnimator();
+    MOZ_ASSERT(animator);
+    animator->UpdateRootFrameMetrics(mFrameMetrics);
+  }
+#endif
   if (RefPtr<GeckoContentController> controller = GetGeckoContentController()) {
     if (!IsTransformingState(aOldState) && IsTransformingState(aNewState)) {
       controller->NotifyAPZStateChange(
           GetGuid(), APZStateChange::eTransformBegin);
 #if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
       // Let the compositor know about scroll state changes so it can manage
       // windowed plugins.
       if (gfxPrefs::HidePluginsForScroll() && mCompositorController) {