add FlipX() and FlipY() funtion in DOMMatrixReadOnly.

third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.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 "core/dom/DOMMatrix.h"
 
 namespace blink {
 
 DOMMatrixReadOnly* DOMMatrixReadOnly::create(Vector<double> sequence, ExceptionState& exceptionState)
 {
@@ skipping 56 matching lines @@
 {
     return DOMMatrix::create(this)->scale3dSelf(scale, ox, oy, oz);
 }
 
 DOMMatrix* DOMMatrixReadOnly::scaleNonUniform(double sx, double sy, double sz,
     double ox, double oy, double oz)
 {
     return DOMMatrix::create(this)->scaleNonUniformSelf(sx, sy, sz, ox, oy, oz);
 }
 
+DOMMatrix* DOMMatrixReadOnly::flipX()

[zino, 2016/08/20 11:47:16]

IMHO, this function is simplified like this:
ctm = getCTM()
return -1 * left side elements(m11, m12, m13, m14) of ctm

[Hwanseung Lee, 2016/08/20 13:13:12]

Done.

+{
+    DOMMatrix* filpX = DOMMatrix::create();

[zino, 2016/08/20 11:47:16]

At this time, flipX is identity matrix. So, setA(-1) is enough.

+    filpX->setA(-1);
+    filpX->setB(0);
+    filpX->setC(0);
+    filpX->setD(1);
+    filpX->setE(0);
+    filpX->setF(0);
+    return DOMMatrix::create(this)->multiplySelf(filpX);
+}
+
+DOMMatrix* DOMMatrixReadOnly::flipY()
+{
+    DOMMatrix* filpY = DOMMatrix::create();
+    filpY->setA(1);
+    filpY->setB(0);
+    filpY->setC(0);
+    filpY->setD(-1);

[zino, 2016/08/20 11:47:16]

ditto

+    filpY->setE(0);
+    filpY->setF(0);
+    return DOMMatrix::create(this)->multiplySelf(filpY);
+}
+
 DOMFloat32Array* DOMMatrixReadOnly::toFloat32Array() const
 {
     float array[] = {
         static_cast<float>(m_matrix->m11()), static_cast<float>(m_matrix->m12()), static_cast<float>(m_matrix->m13()), static_cast<float>(m_matrix->m14()),
         static_cast<float>(m_matrix->m21()), static_cast<float>(m_matrix->m22()), static_cast<float>(m_matrix->m23()), static_cast<float>(m_matrix->m24()),
         static_cast<float>(m_matrix->m31()), static_cast<float>(m_matrix->m32()), static_cast<float>(m_matrix->m33()), static_cast<float>(m_matrix->m34()),
         static_cast<float>(m_matrix->m41()), static_cast<float>(m_matrix->m42()), static_cast<float>(m_matrix->m43()), static_cast<float>(m_matrix->m44())
     };
 
     return DOMFloat32Array::create(array, 16);
 }
 
 DOMFloat64Array* DOMMatrixReadOnly::toFloat64Array() const
 {
     double array[] = {
         m_matrix->m11(), m_matrix->m12(), m_matrix->m13(), m_matrix->m14(),
         m_matrix->m21(), m_matrix->m22(), m_matrix->m23(), m_matrix->m24(),
         m_matrix->m31(), m_matrix->m32(), m_matrix->m33(), m_matrix->m34(),
         m_matrix->m41(), m_matrix->m42(), m_matrix->m43(), m_matrix->m44()
     };
 
     return DOMFloat64Array::create(array, 16);
 }
 
 } // namespace blink