WIP: Prototype using "dictionary schema" to do bulk read for DOMMatrixInit.

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

Index: third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.idl
diff --git a/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.idl b/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.idl
index b946fa73547aee6e2ab3db5a075fbf7f122e1672..41c8604c534679527d8884b20989da1978f3a966 100644
--- a/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.idl
+++ b/third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.idl
@@ -69,7 +69,7 @@
                               optional unrestricted double angle = 0);
     DOMMatrix skewX(optional unrestricted double sx = 0);
     DOMMatrix skewY(optional unrestricted double sy = 0);
-    [RaisesException] DOMMatrix multiply(optional DOMMatrixInit other);
+    [Custom, RaisesException] DOMMatrix multiply(optional DOMMatrixInit other);
     DOMMatrix flipX();
     DOMMatrix flipY();
     DOMMatrix inverse();