diff -r 000000000000 -r 6474c204b198 content/base/src/nsDOMCaretPosition.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/base/src/nsDOMCaretPosition.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,75 @@
+/* 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 "nsDOMCaretPosition.h"
+
+#include "mozilla/dom/CaretPositionBinding.h"
+#include "mozilla/dom/DOMRect.h"
+#include "nsRange.h"
+
+using namespace mozilla::dom;
+
+nsDOMCaretPosition::nsDOMCaretPosition(nsINode* aNode, uint32_t aOffset)
+  : mOffset(aOffset), mOffsetNode(aNode), mAnonymousContentNode(nullptr)
+{
+  SetIsDOMBinding();
+}
+
+nsDOMCaretPosition::~nsDOMCaretPosition()
+{
+}
+
+nsINode* nsDOMCaretPosition::GetOffsetNode() const
+{
+  return mOffsetNode;
+}
+
+already_AddRefed<DOMRect>
+nsDOMCaretPosition::GetClientRect() const
+{
+  if (!mOffsetNode) {
+    return nullptr;
+  }
+
+  nsRefPtr<DOMRect> rect;
+  nsRefPtr<nsRange> domRange;
+  nsCOMPtr<nsINode> node;
+
+  if (mAnonymousContentNode) {
+    node = mAnonymousContentNode;
+  } else {
+    node = mOffsetNode;
+  }
+
+  nsresult creationRv = nsRange::CreateRange(node, mOffset, node,
+                                             mOffset,
+                                             getter_AddRefs<nsRange>(domRange));
+  if (!NS_SUCCEEDED(creationRv)) {
+    return nullptr;
+  }
+
+  NS_ASSERTION(domRange, "unable to retrieve valid dom range from CaretPosition");
+
+  rect = domRange->GetBoundingClientRect();
+
+  return rect.forget();
+}
+
+JSObject*
+nsDOMCaretPosition::WrapObject(JSContext *aCx)
+{
+  return mozilla::dom::CaretPositionBinding::Wrap(aCx, this);
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_2(nsDOMCaretPosition,
+                                        mOffsetNode, mAnonymousContentNode)
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMCaretPosition)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMCaretPosition)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMCaretPosition)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+