Implement skew*() methods in DOMMatrix.

Source/core/dom/DOMMatrixReadOnly.idl

Index: Source/core/dom/DOMMatrixReadOnly.idl
diff --git a/Source/core/dom/DOMMatrixReadOnly.idl b/Source/core/dom/DOMMatrixReadOnly.idl
index 730bf941c10b38767314fbc0a9b242723827dad7..549e15067e63002ff3ad23e0fe2907805532e468 100644
--- a/Source/core/dom/DOMMatrixReadOnly.idl
+++ b/Source/core/dom/DOMMatrixReadOnly.idl
@@ -36,7 +36,6 @@
 
     // FIXME: Should implement some methods (See: crbug.com/388780)
     // Immutable transform methods
-    DOMMatrix multiply(DOMMatrix other);
     DOMMatrix translate(unrestricted double tx,
                         unrestricted double ty,
                         optional unrestricted double tz = 0);
@@ -62,6 +61,9 @@
                               unrestricted double y,
                               unrestricted double z,
                               unrestricted double angle);
+    DOMMatrix skewX(unrestricted double sx);
+    DOMMatrix skewY(unrestricted double sy);
+    DOMMatrix multiply(DOMMatrix other);
 
     Float32Array toFloat32Array();
     Float64Array toFloat64Array();