Stop accepting string constructor of DOMMatrix on workers

third_party/WebKit/Source/core/geometry/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 "core/geometry/DOMMatrix.h"
 
 namespace blink {
 
-DOMMatrix* DOMMatrix::Create(ExceptionState& exception_state) {
+DOMMatrix* DOMMatrix::Create(ExecutionContext* execution_context,
+                             ExceptionState& exception_state) {
   return new DOMMatrix(TransformationMatrix());
 }
 
-DOMMatrix* DOMMatrix::Create(StringOrUnrestrictedDoubleSequence& init,
+DOMMatrix* DOMMatrix::Create(ExecutionContext* execution_context,
+                             StringOrUnrestrictedDoubleSequence& init,
                              ExceptionState& exception_state) {
   if (init.isString()) {
+    if (execution_context->IsWorkerOrWorkletGlobalScope()) {

[foolip, 2017/05/11 18:59:47]

To stay pedantically close to the spec and leave no doubt about the only place
it *does* work, !execution_context->IsDocument() instead?

[fserb, 2017/05/11 19:13:55]

yes! That's the thing we were not sure. Thanks :)

+      exception_state.ThrowTypeError(
+          "String constructor can't be used on workers.");
+      return nullptr;
+    }
+
     DOMMatrix* matrix = new DOMMatrix(TransformationMatrix());
     matrix->SetMatrixValueFromString(init.getAsString(), exception_state);
     return matrix;
   }
 
   if (init.isUnrestrictedDoubleSequence()) {
     const Vector<double>& sequence = init.getAsUnrestrictedDoubleSequence();
     if (sequence.size() != 6 && sequence.size() != 16) {
       exception_state.ThrowTypeError(
           "The sequence must contain 6 elements for a 2D matrix or 16 elements "
@@ skipping 241 matching lines @@
   return this;
 }
 
 DOMMatrix* DOMMatrix::setMatrixValue(const String& input_string,
                                      ExceptionState& exception_state) {
   SetMatrixValueFromString(input_string, exception_state);
   return this;
 }
 
 }  // namespace blink