diff --git a/xpcom/ds/nsISupportsArray.idl b/xpcom/ds/nsISupportsArray.idl
index cdf7fbc3fb56..1a92cf2c1fa7 100644
--- a/xpcom/ds/nsISupportsArray.idl
+++ b/xpcom/ds/nsISupportsArray.idl
@@ -54,6 +54,9 @@ interface nsISupportsArray : nsICollection {
   
 
   nsISupportsArray clone();
+
+  [notxpcom] boolean RemoveElementsAt(in unsigned long aIndex,
+                                      in unsigned long aCount);
 };
 
 %{C++
diff --git a/xpcom/ds/nsSupportsArray.cpp b/xpcom/ds/nsSupportsArray.cpp
index 2a94f3e5bcbe..a37bcc2364bd 100644
--- a/xpcom/ds/nsSupportsArray.cpp
+++ b/xpcom/ds/nsSupportsArray.cpp
@@ -283,15 +283,16 @@ nsSupportsArray::ReplaceElementAt(nsISupports* aElement, uint32_t aIndex)
 }
 
 NS_IMETHODIMP_(bool)
-nsSupportsArray::RemoveElementAt(uint32_t aIndex)
+nsSupportsArray::RemoveElementsAt(uint32_t aIndex, uint32_t aCount)
 {
-  if (aIndex + 1 <= mCount) {
-    NS_IF_RELEASE(mArray[aIndex]);
-
-    mCount -= 1;
+  if (aIndex + aCount <= mCount) {
+    for (uint32_t i = 0; i < aCount; i++) {
+      NS_IF_RELEASE(mArray[aIndex + i]);
+    }
+    mCount -= aCount;
     int32_t slide = (mCount - aIndex);
     if (0 < slide) {
-      ::memmove(mArray + aIndex, mArray + aIndex + 1,
+      ::memmove(mArray + aIndex, mArray + aIndex + aCount,
                 slide * sizeof(nsISupports*));
     }
     return true;
diff --git a/xpcom/ds/nsSupportsArray.h b/xpcom/ds/nsSupportsArray.h
index e927a63689eb..86f806de9d1a 100644
--- a/xpcom/ds/nsSupportsArray.h
+++ b/xpcom/ds/nsSupportsArray.h
@@ -82,7 +82,10 @@ public:
   ReplaceElementAt(nsISupports* aElement, uint32_t aIndex) override;
 
   MOZ_MUST_USE NS_IMETHOD_(bool)
-  RemoveElementAt(uint32_t aIndex) override;
+  RemoveElementAt(uint32_t aIndex) override
+  {
+    return RemoveElementsAt(aIndex, 1);
+  }
 
   MOZ_MUST_USE NS_IMETHOD DeleteElementAt(uint32_t aIndex) override
   {
@@ -93,6 +96,9 @@ public:
 
   MOZ_MUST_USE NS_IMETHOD Clone(nsISupportsArray** aResult) override;
 
+  MOZ_MUST_USE NS_IMETHOD_(bool)
+  RemoveElementsAt(uint32_t aIndex, uint32_t aCount) override;
+
 protected:
   void DeleteArray(void);