diff -r 000000000000 -r 6474c204b198 content/canvas/src/TextMetrics.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/canvas/src/TextMetrics.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 2; 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/. */
+
+#ifndef mozilla_dom_TextMetrics_h
+#define mozilla_dom_TextMetrics_h
+
+#include "mozilla/dom/CanvasRenderingContext2DBinding.h"
+#include "mozilla/dom/NonRefcountedDOMObject.h"
+
+namespace mozilla {
+namespace dom {
+
+class TextMetrics MOZ_FINAL : public NonRefcountedDOMObject
+{
+public:
+  TextMetrics(float w) : width(w)
+  {
+    MOZ_COUNT_CTOR(TextMetrics);
+  }
+
+  ~TextMetrics()
+  {
+    MOZ_COUNT_DTOR(TextMetrics);
+  }
+
+  float Width() const
+  {
+    return width;
+  }
+
+  JSObject* WrapObject(JSContext* aCx, bool* aTookOwnership)
+  {
+    return TextMetricsBinding::Wrap(aCx, this, aTookOwnership);
+  }
+
+private:
+  float width;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_TextMetrics_h