diff --git a/content/base/public/nsIDocument.h b/content/base/public/nsIDocument.h
index 54a9316db69..cac86556e7c 100644
--- a/content/base/public/nsIDocument.h
+++ b/content/base/public/nsIDocument.h
@@ -79,8 +79,8 @@ class Element;
 } // namespace mozilla
 
 #define NS_IDOCUMENT_IID \
-{ 0x57fe44ae, 0x6656, 0x44b8, \
-  { 0x8d, 0xc0, 0xfc, 0xa7, 0x43, 0x28, 0xbe, 0x86 } }
+{ 0x0e1324c9, 0xc997, 0x447e, \
+  { 0xbc, 0xd9, 0xa6, 0x57, 0x80, 0x29, 0x91, 0xe4 } }
 
 // Flag for AddStyleSheet().
 #define NS_STYLESHEET_FROM_CATALOG                (1 << 0)
@@ -1621,7 +1621,10 @@ public:
 
   // Add/Remove images from the document image tracker
   virtual nsresult AddImage(imgIRequest* aImage) = 0;
-  virtual nsresult RemoveImage(imgIRequest* aImage) = 0;
+  // If the REQUEST_DISCARD flag is passed then if the lock count is zero we
+  // will request the image be discarded now (instead of waiting).
+  enum { REQUEST_DISCARD = 0x1 };
+  virtual nsresult RemoveImage(imgIRequest* aImage, uint32_t aFlags = 0) = 0;
 
   // Makes the images on this document locked/unlocked. By default, the locking
   // state is unlocked/false.
diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index fde7e2d7383..c4cf12796f7 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -8424,7 +8424,7 @@ nsDocument::NotifyAudioAvailableListener()
 }
 
 nsresult
-nsDocument::RemoveImage(imgIRequest* aImage)
+nsDocument::RemoveImage(imgIRequest* aImage, uint32_t aFlags)
 {
   NS_ENSURE_ARG_POINTER(aImage);
 
@@ -8460,10 +8460,12 @@ nsDocument::RemoveImage(imgIRequest* aImage)
     rv = NS_SUCCEEDED(rv) ? rv2 : rv;
   }
 
-  // Request that the image be discarded if nobody else holds a lock on it.
-  // Do this even if !mLockingImages, because even if we didn't just unlock
-  // this image, it might still be a candidate for discarding.
-  aImage->RequestDiscard();
+  if (aFlags & REQUEST_DISCARD) {
+    // Request that the image be discarded if nobody else holds a lock on it.
+    // Do this even if !mLockingImages, because even if we didn't just unlock
+    // this image, it might still be a candidate for discarding.
+    aImage->RequestDiscard();
+  }
 
   return rv;
 }
diff --git a/content/base/src/nsDocument.h b/content/base/src/nsDocument.h
index 972c4c39e58..f9a620900c5 100644
--- a/content/base/src/nsDocument.h
+++ b/content/base/src/nsDocument.h
@@ -915,7 +915,7 @@ public:
   virtual Element *LookupImageElement(const nsAString& aElementId);
 
   virtual NS_HIDDEN_(nsresult) AddImage(imgIRequest* aImage);
-  virtual NS_HIDDEN_(nsresult) RemoveImage(imgIRequest* aImage);
+  virtual NS_HIDDEN_(nsresult) RemoveImage(imgIRequest* aImage, uint32_t aFlags);
   virtual NS_HIDDEN_(nsresult) SetImageLockingState(bool aLocked);
 
   // AddPlugin adds a plugin-related element to mPlugins when the element is
diff --git a/content/base/src/nsImageLoadingContent.cpp b/content/base/src/nsImageLoadingContent.cpp
index 626a94bb5b0..ffc6764b4a4 100644
--- a/content/base/src/nsImageLoadingContent.cpp
+++ b/content/base/src/nsImageLoadingContent.cpp
@@ -1183,9 +1183,9 @@ nsImageLoadingContent::UnbindFromTree(bool aDeep, bool aNullParent)
   pusher.PushNull();
 
   if (mCurrentRequestFlags & REQUEST_SHOULD_BE_TRACKED)
-    doc->RemoveImage(mCurrentRequest);
+    doc->RemoveImage(mCurrentRequest, nsIDocument::REQUEST_DISCARD);
   if (mPendingRequestFlags & REQUEST_SHOULD_BE_TRACKED)
-    doc->RemoveImage(mPendingRequest);
+    doc->RemoveImage(mPendingRequest, nsIDocument::REQUEST_DISCARD);
 }
 
 nsresult
@@ -1227,7 +1227,7 @@ nsImageLoadingContent::UntrackImage(imgIRequest* aImage)
   // all locked images on destruction.
   nsIDocument* doc = GetOurCurrentDoc();
   if (doc)
-    return doc->RemoveImage(aImage);
+    return doc->RemoveImage(aImage, nsIDocument::REQUEST_DISCARD);
   return NS_OK;
 }
 
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index b0c637da8d0..60d17b3c197 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -580,7 +580,7 @@ nsStyleBorder::UntrackImage(nsPresContext* aContext)
   // Unregister the image with the document
   nsIDocument* doc = aContext->Document();
   if (doc)
-    doc->RemoveImage(mBorderImageSource);
+    doc->RemoveImage(mBorderImageSource, nsIDocument::REQUEST_DISCARD);
 
   // Mark state
 #ifdef DEBUG
@@ -1507,7 +1507,7 @@ nsStyleImage::UntrackImage(nsPresContext* aContext)
   // Unregister the image with the document
   nsIDocument* doc = aContext->Document();
   if (doc)
-    doc->RemoveImage(mImage);
+    doc->RemoveImage(mImage, nsIDocument::REQUEST_DISCARD);
 
   // Mark state
 #ifdef DEBUG
@@ -2408,7 +2408,7 @@ nsStyleContentData::UntrackImage(nsPresContext* aContext)
   // Unregister the image with the document
   nsIDocument* doc = aContext->Document();
   if (doc)
-    doc->RemoveImage(mContent.mImage);
+    doc->RemoveImage(mContent.mImage, nsIDocument::REQUEST_DISCARD);
 
   // Mark state
 #ifdef DEBUG