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

third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.cpp

Index: third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.cpp
diff --git a/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.cpp b/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.cpp
index d52416b1babe4f8fda10f4860f0b77ac22d8d3b0..fdecf996156e9451b276a746bb9107dd93a47a43 100644
--- a/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.cpp
+++ b/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.cpp
@@ -74,6 +74,30 @@ DOMMatrix* DOMMatrixReadOnly::scaleNonUniform(double sx, double sy, double sz,
     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[] = {