diff -r 000000000000 -r 6474c204b198 layout/base/MaskLayerImageCache.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/base/MaskLayerImageCache.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MaskLayerImageCache.h"
+#include "ImageContainer.h"
+
+using namespace mozilla::layers;
+
+namespace mozilla {
+
+MaskLayerImageCache::MaskLayerImageCache()
+{
+  MOZ_COUNT_CTOR(MaskLayerImageCache);
+}
+MaskLayerImageCache::~MaskLayerImageCache()
+{
+  MOZ_COUNT_DTOR(MaskLayerImageCache);
+}
+
+
+/* static */ PLDHashOperator
+MaskLayerImageCache::SweepFunc(MaskLayerImageEntry* aEntry,
+                               void* aUserArg)
+{
+  const MaskLayerImageCache::MaskLayerImageKey* key = aEntry->mKey;
+
+  if (key->mLayerCount == 0) {
+    return PL_DHASH_REMOVE;
+  }
+
+  return PL_DHASH_NEXT;
+}
+
+void
+MaskLayerImageCache::Sweep() 
+{
+  mMaskImageContainers.EnumerateEntries(SweepFunc, nullptr);
+}
+
+ImageContainer*
+MaskLayerImageCache::FindImageFor(const MaskLayerImageKey** aKey)
+{
+  if (MaskLayerImageEntry* entry = mMaskImageContainers.GetEntry(**aKey)) {
+    *aKey = entry->mKey.get();
+    return entry->mContainer;
+  }
+
+  return nullptr;
+}
+
+void
+MaskLayerImageCache::PutImage(const MaskLayerImageKey* aKey, ImageContainer* aContainer)
+{
+  MaskLayerImageEntry* entry = mMaskImageContainers.PutEntry(*aKey);
+  entry->mContainer = aContainer;
+}
+
+}