diff --git a/layout/base/RestyleManager.cpp b/layout/base/RestyleManager.cpp
index fe55750d358c..481bd2c23458 100644
--- a/layout/base/RestyleManager.cpp
+++ b/layout/base/RestyleManager.cpp
@@ -785,9 +785,11 @@ RestyleManager::ProcessRestyledFrames(nsStyleChangeList& aChangeList)
         // frame does not maintain overflow rects, so avoid calling
         // FinishAndStoreOverflow on it:
         hint = NS_SubtractHint(hint,
-                 NS_CombineHint(nsChangeHint_UpdateOverflow,
-                   NS_CombineHint(nsChangeHint_ChildrenOnlyTransform,
-                                  nsChangeHint_UpdatePostTransformOverflow)));
+                 NS_CombineHint(
+                   NS_CombineHint(nsChangeHint_UpdateOverflow,
+                                  nsChangeHint_ChildrenOnlyTransform),
+                   NS_CombineHint(nsChangeHint_UpdatePostTransformOverflow,
+                                  nsChangeHint_UpdateParentOverflow)));
       }
 
       if (!(frame->GetStateBits() & NS_FRAME_MAY_BE_TRANSFORMED)) {
@@ -829,11 +831,12 @@ RestyleManager::ProcessRestyledFrames(nsStyleChangeList& aChangeList)
       if (!didReflowThisFrame &&
           (hint & (nsChangeHint_UpdateOverflow |
                    nsChangeHint_UpdatePostTransformOverflow |
+                   nsChangeHint_UpdateParentOverflow |
                    nsChangeHint_UpdateSubtreeOverflow))) {
         if (hint & nsChangeHint_UpdateSubtreeOverflow) {
+          // FIXME (bug 1133392): Continuations?
           AddSubtreeToOverflowTracker(frame);
         }
-        OverflowChangedTracker::ChangeKind changeKind;
         if (hint & nsChangeHint_ChildrenOnlyTransform) {
           // The overflow areas of the child frames need to be updated:
           nsIFrame* hintFrame = GetFrameForChildrenOnlyTransformHint(frame);
@@ -865,18 +868,37 @@ RestyleManager::ProcessRestyledFrames(nsStyleChangeList& aChangeList)
         // overflows since that will happen when it's reflowed.
         if (!(frame->GetStateBits() &
               (NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN))) {
-          // If we have both nsChangeHint_UpdateOverflow and
-          // nsChangeHint_UpdatePostTransformOverflow, CHILDREN_AND_PARENT_CHANGED
-          // is selected as it is stronger.
-          if (hint & (nsChangeHint_UpdateOverflow | 
-                      nsChangeHint_UpdateSubtreeOverflow)) {
-            changeKind = OverflowChangedTracker::CHILDREN_AND_PARENT_CHANGED;
-          } else {
-            changeKind = OverflowChangedTracker::TRANSFORM_CHANGED;
+          if (hint & (nsChangeHint_UpdateOverflow |
+                      nsChangeHint_UpdateSubtreeOverflow |
+                      nsChangeHint_UpdatePostTransformOverflow)) {
+            OverflowChangedTracker::ChangeKind changeKind;
+            // If we have both nsChangeHint_UpdateOverflow and
+            // nsChangeHint_UpdatePostTransformOverflow,
+            // CHILDREN_AND_PARENT_CHANGED is selected as it is
+            // strictly stronger.
+            if (hint & (nsChangeHint_UpdateOverflow |
+                        nsChangeHint_UpdateSubtreeOverflow)) {
+              changeKind = OverflowChangedTracker::CHILDREN_AND_PARENT_CHANGED;
+            } else {
+              changeKind = OverflowChangedTracker::TRANSFORM_CHANGED;
+            }
+            for (nsIFrame *cont = frame; cont; cont =
+                   nsLayoutUtils::GetNextContinuationOrIBSplitSibling(cont)) {
+              mOverflowChangedTracker.AddFrame(cont, changeKind);
+            }
           }
-          for (nsIFrame *cont = frame; cont; cont =
-                 nsLayoutUtils::GetNextContinuationOrIBSplitSibling(cont)) {
-            mOverflowChangedTracker.AddFrame(cont, changeKind);
+          // UpdateParentOverflow hints need to be processed in addition
+          // to the above, since if the processing of the above hints
+          // yields no change, the update will not propagate to the
+          // parent.
+          if (hint & nsChangeHint_UpdateParentOverflow) {
+            MOZ_ASSERT(frame->GetParent(),
+                       "shouldn't get style hints for the root frame");
+            for (nsIFrame *cont = frame; cont; cont =
+                   nsLayoutUtils::GetNextContinuationOrIBSplitSibling(cont)) {
+              mOverflowChangedTracker.AddFrame(cont->GetParent(),
+                                   OverflowChangedTracker::CHILDREN_CHANGED);
+            }
           }
         }
       }
@@ -4079,6 +4101,7 @@ RestyleManager::ChangeHintToString(nsChangeHint aHint)
     "UpdateCursor", "UpdateEffects", "UpdateOpacityLayer",
     "UpdateTransformLayer", "ReconstructFrame", "UpdateOverflow",
     "UpdateSubtreeOverflow", "UpdatePostTransformOverflow",
+    "UpdateParentOverflow",
     "ChildrenOnlyTransform", "RecomputePosition", "AddOrRemoveTransform",
     "BorderStyleNoneChange", "UpdateTextPath", "NeutralChange",
     "InvalidateRenderingObservers"
diff --git a/layout/base/nsChangeHint.h b/layout/base/nsChangeHint.h
index 65a7431c4a63..24762c692238 100644
--- a/layout/base/nsChangeHint.h
+++ b/layout/base/nsChangeHint.h
@@ -86,15 +86,27 @@ enum nsChangeHint {
 
   /**
    * The frame's overflow area has changed, through a change in its transform.
+   * In other words, the frame's pre-transform overflow is unchanged, but
+   * its post-transform overflow has changed, and thus its effect on its
+   * parent's overflow has changed.  If the pre-transform overflow has
+   * changed, see nsChangeHint_UpdateOverflow.
    * Does not update any descendant frames.
    */
   nsChangeHint_UpdatePostTransformOverflow = 0x2000,
 
+  /**
+   * This frame's effect on its parent's overflow area has changed.
+   * (But neither its pre-transform nor post-transform overflow have
+   * changed; if those are the case, see
+   * nsChangeHint_UpdatePostTransformOverflow.)
+   */
+  nsChangeHint_UpdateParentOverflow = 0x4000,
+
   /**
    * The children-only transform of an SVG frame changed, requiring the
    * overflow rects of the frame's immediate children to be updated.
    */
-  nsChangeHint_ChildrenOnlyTransform = 0x4000,
+  nsChangeHint_ChildrenOnlyTransform = 0x8000,
 
   /**
    * The frame's offsets have changed, while its dimensions might have
@@ -106,7 +118,7 @@ enum nsChangeHint {
    * nsChangeHint_UpdateOverflow in order to get the overflow areas of
    * the ancestors updated as well.
    */
-  nsChangeHint_RecomputePosition = 0x8000,
+  nsChangeHint_RecomputePosition = 0x10000,
 
   /**
    * Behaves like ReconstructFrame, but only if the frame has descendants
@@ -114,7 +126,7 @@ enum nsChangeHint {
    * has changed whether the frame is a container for fixed-pos or abs-pos
    * elements, but reframing is otherwise not needed.
    */
-  nsChangeHint_AddOrRemoveTransform = 0x10000,
+  nsChangeHint_AddOrRemoveTransform = 0x20000,
 
   /**
    * This change hint has *no* change handling behavior.  However, it
@@ -122,19 +134,19 @@ enum nsChangeHint {
    * changes, and it's inherited by a child, that might require a reflow
    * due to the border-width change on the child.
    */
-  nsChangeHint_BorderStyleNoneChange = 0x20000,
+  nsChangeHint_BorderStyleNoneChange = 0x40000,
 
   /**
    * SVG textPath needs to be recomputed because the path has changed.
    * This means that the glyph positions of the text need to be recomputed.
    */
-  nsChangeHint_UpdateTextPath = 0x40000,
+  nsChangeHint_UpdateTextPath = 0x80000,
 
   /**
    * This will schedule an invalidating paint. This is useful if something
    * has changed which will be invalidated by DLBI.
    */
-  nsChangeHint_SchedulePaint = 0x80000,
+  nsChangeHint_SchedulePaint = 0x100000,
 
   /**
    * A hint reflecting that style data changed with no change handling
@@ -150,12 +162,12 @@ enum nsChangeHint {
    * different data would be cached information that would be re-calculated
    * to the same values, such as nsStyleBorder::mSubImages.)
    */
-  nsChangeHint_NeutralChange = 0x100000,
+  nsChangeHint_NeutralChange = 0x200000,
 
   /**
    * This will cause rendering observers to be invalidated.
    */
-  nsChangeHint_InvalidateRenderingObservers = 0x200000
+  nsChangeHint_InvalidateRenderingObservers = 0x400000
 
   // IMPORTANT NOTE: When adding new hints, consider whether you need to
   // add them to NS_HintsNotHandledForDescendantsIn() below.  Please also
@@ -214,6 +226,7 @@ inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
           nsChangeHint_UpdateOpacityLayer | \
           nsChangeHint_UpdateOverflow | \
           nsChangeHint_UpdatePostTransformOverflow | \
+          nsChangeHint_UpdateParentOverflow | \
           nsChangeHint_ChildrenOnlyTransform | \
           nsChangeHint_RecomputePosition | \
           nsChangeHint_AddOrRemoveTransform | \
@@ -229,6 +242,7 @@ inline nsChangeHint NS_HintsNotHandledForDescendantsIn(nsChangeHint aChangeHint)
     nsChangeHint_UpdateOpacityLayer |
     nsChangeHint_UpdateOverflow |
     nsChangeHint_UpdatePostTransformOverflow |
+    nsChangeHint_UpdateParentOverflow |
     nsChangeHint_ChildrenOnlyTransform |
     nsChangeHint_RecomputePosition |
     nsChangeHint_AddOrRemoveTransform |