Implement translate() and translateSelf() in DOMMatrix.

Source/core/dom/DOMMatrixReadOnly.cpp

Index: Source/core/dom/DOMMatrixReadOnly.cpp
diff --git a/Source/core/dom/DOMMatrixReadOnly.cpp b/Source/core/dom/DOMMatrixReadOnly.cpp
index b92e085fe9ce15f96a904215a06af431be9920fd..9f8ab94ddeb46860f6f28db5584b2023128c1537 100644
--- a/Source/core/dom/DOMMatrixReadOnly.cpp
+++ b/Source/core/dom/DOMMatrixReadOnly.cpp
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 #include "config.h"
-#include "core/dom/DOMMatrixReadOnly.h"
+#include "core/dom/DOMMatrix.h"
 
 namespace blink {
 
@@ -17,4 +17,9 @@ bool DOMMatrixReadOnly::isIdentity() const
     return m_matrix.isIdentity();
 }
 
+DOMMatrix* DOMMatrixReadOnly::translate(double tx, double ty, double tz)
+{
+    return DOMMatrix::create(this)->translateSelf(tx, ty, tz);
+}
+
 } // namespace blink