2 files changed, 23 insertions, 1 deletions
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 1a3f5b5ca..ffe50a015 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -9843,4 +9843,18 @@ nsContentUtils::IsLocalRefURL(const nsString& aString)
   }
 
   return false;
-}
-\ No newline at end of file
+}
+
+/* static */ uint32_t
+nsContentUtils::GetNodeDepth(nsINode* aNode)
+{
+  uint32_t depth = 1;
+
+  MOZ_ASSERT(aNode, "Node shouldn't be null");
+
+  while ((aNode = aNode->GetParentNode())) {
+    ++depth;
+  }
+
+  return depth;
+}
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index ffbd15e78..08587b5e4 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -2745,6 +2745,14 @@ public:
   static bool
   IsLocalRefURL(const nsString& aString);
 
+  /**
+   * Returns the length of the parent-traversal path (in terms of the number of
+   * nodes) to an unparented/root node from aNode. An unparented/root node is
+   * considered to have a depth of 1, its children have a depth of 2, etc.
+   * aNode is expected to be non-null.
+   */
+  static uint32_t GetNodeDepth(nsINode* aNode);
+
 private:
   static bool InitializeEventTable();