Implement translate() and translateSelf() in DOMMatrix.

Source/core/dom/DOMMatrix.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/dom/DOMMatrix.h"
 
 namespace blink {
 
 DOMMatrix* DOMMatrix::create()
@@ skipping 11 matching lines @@
     m_matrix = matrix;
     m_is2D = is2D;
 }
 
 void DOMMatrix::setIs2D(bool value)
 {
     if (m_is2D)
         m_is2D = value;
 }
 
+DOMMatrix* DOMMatrix::translateSelf(double tx, double ty, double tz)
+{
+    if (!tx && !ty && !tz)
+        return this;
+
+    if (tz)
+        m_is2D = false;
+
+    if (m_matrix.isIdentity()) {

[krit, 2014/08/16 07:03:06]

Just use translate3d() and translate() don't duplicate code. The isIdentity
check shouldn't be here.

[zino, 2014/08/16 16:50:42]

Okay, I agree with you. I'll remove the codes.

+        m_matrix.setM41(tx);
+        m_matrix.setM42(ty);
+        m_matrix.setM43(tz);
+        return this;
+    }
+
+    if (m_is2D) {
+        m_matrix.setM41(m_matrix.m41() + tx * m_matrix.m11() + ty * m_matrix.m21());

[zino, 2014/08/16 16:50:42]

However, I think it is better to leave this codes than using translate().
We don't need calculate m33, m34 because DOMMatrix has the |m_is2D|.
(When m_is2D is true)

+        m_matrix.setM42(m_matrix.m42() + tx * m_matrix.m12() + ty * m_matrix.m22());
+        return this;
+    }
+
+    m_matrix.translate3d(tx, ty, tz);
+
+    return this;
+}
+
 } // namespace blink