--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -273,16 +273,21 @@ using mozilla::gfx::PointTyped;
  *
  * \li\b apz.overscroll.stop_distance_threshold
  * \li\b apz.overscroll.stop_velocity_threshold
  * Thresholds for stopping the overscroll animation. When both the distance
  * and the velocity fall below their thresholds, we stop oscillating.\n
  * Units: screen pixels (for distance)
  *        screen pixels per millisecond (for velocity)
  *
+ * \li\b apz.paint_skipping.enabled
+ * When APZ is scrolling and sending repaint requests to the main thread, often
+ * the main thread doesn't actually need to do a repaint. This pref allows the
+ * main thread to skip doing those repaints in cases where it doesn't need to.
+ *
  * \li\b apz.record_checkerboarding
  * Whether or not to record detailed info on checkerboarding events.
  *
  * \li\b apz.test.logging_enabled
  * Enable logging of APZ test data (see bug 961289).
  *
  * \li\b apz.touch_move_tolerance
  * See the description for apz.touch_start_tolerance below. This is a similar

--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -169,16 +169,17 @@ private:
   DECL_GFX_PREF(Live, "apz.minimap.enabled",                   APZMinimap, bool, false);
   DECL_GFX_PREF(Live, "apz.overscroll.enabled",                APZOverscrollEnabled, bool, false);
   DECL_GFX_PREF(Live, "apz.overscroll.min_pan_distance_ratio", APZMinPanDistanceRatio, float, 1.0f);
   DECL_GFX_PREF(Live, "apz.overscroll.spring_friction",        APZOverscrollSpringFriction, float, 0.015f);
   DECL_GFX_PREF(Live, "apz.overscroll.spring_stiffness",       APZOverscrollSpringStiffness, float, 0.001f);
   DECL_GFX_PREF(Live, "apz.overscroll.stop_distance_threshold", APZOverscrollStopDistanceThreshold, float, 5.0f);
   DECL_GFX_PREF(Live, "apz.overscroll.stop_velocity_threshold", APZOverscrollStopVelocityThreshold, float, 0.01f);
   DECL_GFX_PREF(Live, "apz.overscroll.stretch_factor",         APZOverscrollStretchFactor, float, 0.5f);
+  DECL_GFX_PREF(Live, "apz.paint_skipping.enabled",            APZPaintSkipping, bool, true);
   DECL_GFX_PREF(Live, "apz.printtree",                         APZPrintTree, bool, false);
   DECL_GFX_PREF(Live, "apz.record_checkerboarding",            APZRecordCheckerboarding, bool, false);
   DECL_GFX_PREF(Live, "apz.test.logging_enabled",              APZTestLoggingEnabled, bool, false);
   DECL_GFX_PREF(Live, "apz.touch_move_tolerance",              APZTouchMoveTolerance, float, 0.0);
   DECL_GFX_PREF(Live, "apz.touch_start_tolerance",             APZTouchStartTolerance, float, 1.0f/4.5f);
   DECL_GFX_PREF(Live, "apz.velocity_bias",                     APZVelocityBias, float, 1.0f);
   DECL_GFX_PREF(Live, "apz.velocity_relevance_time_ms",        APZVelocityRelevanceTime, uint32_t, 150);
   DECL_GFX_PREF(Live, "apz.x_skate_highmem_adjust",            APZXSkateHighMemAdjust, float, 0.0f);

--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -2661,17 +2661,17 @@ ScrollFrameHelper::ScrollToImpl(nsPoint 
   // Update frame position for scrolling
   mScrolledFrame->SetPosition(mScrollPort.TopLeft() - pt);
   mLastScrollOrigin = aOrigin;
   mLastSmoothScrollOrigin = nullptr;
   mScrollGeneration = ++sScrollGenerationCounter;
 
   ScrollVisual();
 
-  if (LastScrollOrigin() == nsGkAtoms::apz) {
+  if (LastScrollOrigin() == nsGkAtoms::apz && gfxPrefs::APZPaintSkipping()) {
     // If this was an apz scroll and the displayport (relative to the
     // scrolled frame) hasn't changed, then this won't trigger
     // any painting, so no need to schedule one.
     nsRect displayPort;
     DebugOnly<bool> usingDisplayPort =
       nsLayoutUtils::GetDisplayPort(mOuter->GetContent(), &displayPort);
     NS_ASSERTION(usingDisplayPort, "Must have a displayport for apz scrolls!");
 

--- a/layout/xul/nsSliderFrame.cpp
+++ b/layout/xul/nsSliderFrame.cpp
@@ -6,16 +6,18 @@
 //
 // Eric Vaughan
 // Netscape Communications
 //
 // See documentation in associated header file
 //
 
 #include "nsSliderFrame.h"
+
+#include "gfxPrefs.h"
 #include "nsStyleContext.h"
 #include "nsPresContext.h"
 #include "nsIContent.h"
 #include "nsCOMPtr.h"
 #include "nsNameSpaceManager.h"
 #include "nsGkAtoms.h"
 #include "nsHTMLParts.h"
 #include "nsIPresShell.h"
@@ -759,19 +761,22 @@ nsSliderFrame::CurrentPositionChanged()
     newThumbRect.x = snappedThumbLocation.x;
   } else {
     newThumbRect.y = snappedThumbLocation.y;
   }
 
   // set the rect
   thumbFrame->SetRect(newThumbRect);
 
-  // Request a repaint of the scrollbar
+  // Request a repaint of the scrollbar unless we have paint-skipping enabled
+  // and this is an APZ scroll.
   nsIScrollableFrame* scrollableFrame = do_QueryFrame(GetScrollbar()->GetParent());
-  if (!scrollableFrame || scrollableFrame->LastScrollOrigin() != nsGkAtoms::apz) {
+  if (!gfxPrefs::APZPaintSkipping() ||
+      !scrollableFrame ||
+      scrollableFrame->LastScrollOrigin() != nsGkAtoms::apz) {
     SchedulePaint();
   }
 
   mCurPos = curPos;
 
   // inform the parent <scale> if it exists that the value changed
   nsIFrame* parent = GetParent();
   if (parent) {

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -583,16 +583,17 @@ pref("apz.min_skate_speed", "1.0");
 pref("apz.minimap.enabled", false);
 pref("apz.overscroll.enabled", false);
 pref("apz.overscroll.min_pan_distance_ratio", "1.0");
 pref("apz.overscroll.spring_friction", "0.015");
 pref("apz.overscroll.spring_stiffness", "0.0018");
 pref("apz.overscroll.stop_distance_threshold", "5.0");
 pref("apz.overscroll.stop_velocity_threshold", "0.01");
 pref("apz.overscroll.stretch_factor", "0.35");
+pref("apz.paint_skipping.enabled", true);
 
 // Whether to print the APZC tree for debugging
 pref("apz.printtree", false);
 
 #ifdef NIGHTLY_BUILD
 pref("apz.record_checkerboarding", true);
 #else
 pref("apz.record_checkerboarding", false);