--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -2649,21 +2649,45 @@ nsStyleImageLayers::Layer::operator==(co
 }
 
 nsChangeHint
 nsStyleImageLayers::Layer::CalcDifference(const nsStyleImageLayers::Layer& aNewLayer,
                                           nsChangeHint aPositionChangeHint) const
 {
   nsChangeHint hint = nsChangeHint(0);
   if (!EqualURIs(mSourceURI, aNewLayer.mSourceURI)) {
-    hint |= nsChangeHint_UpdateEffects |
-            nsChangeHint_RepaintFrame;
-    // Mask changes require that we update the PreEffectsBBoxProperty,
-    // which is done during overflow computation.
-    hint |= nsChangeHint_UpdateOverflow;
+    hint |= nsChangeHint_RepaintFrame;
+
+    // If Layer::mSourceURI links to a SVG mask, it has a fragment. Not vice
+    // versa. Here are examples of URI contains a fragment, two of them link
+    // to a SVG mask:
+    //   mask:url(a.svg#maskID); // The fragment of this URI is an ID of a mask
+    //                           // element in a.svg.
+    //   mask:url(#localMaskID); // The fragment of this URI is an ID of a mask
+    //                           // element in local document.
+    //   mask:url(b.svg#viewBoxID); // The fragment of this URI is an ID of a
+    //                              // viewbox defined in b.svg.
+    // That is, if mSourceURI has a fragment, it may link to a SVG mask; If
+    // not, it "must" not link to a SVG mask.
+    bool maybeSVGMask = false;
+    if (mSourceURI) {
+      mSourceURI->GetHasRef(&maybeSVGMask);
+    }
+    if (!maybeSVGMask && aNewLayer.mSourceURI) {
+      aNewLayer.mSourceURI->GetHasRef(&maybeSVGMask);
+    }
+
+    // Return nsChangeHint_UpdateEffects and nsChangeHint_UpdateOverflow if
+    // either URI might link to an SVG mask.
+    if (maybeSVGMask) {
+      hint |= nsChangeHint_UpdateEffects;
+      // Mask changes require that we update the PreEffectsBBoxProperty,
+      // which is done during overflow computation.
+      hint |= nsChangeHint_UpdateOverflow;
+    }
   } else if (mAttachment != aNewLayer.mAttachment ||
              mClip != aNewLayer.mClip ||
              mOrigin != aNewLayer.mOrigin ||
              mRepeat != aNewLayer.mRepeat ||
              mBlendMode != aNewLayer.mBlendMode ||
              mSize != aNewLayer.mSize ||
              mImage != aNewLayer.mImage ||
              mMaskMode != aNewLayer.mMaskMode ||