Stop accepting string constructor of DOMMatrix on workers

third_party/WebKit/Source/core/geometry/DOMMatrix.cpp

Index: third_party/WebKit/Source/core/geometry/DOMMatrix.cpp
diff --git a/third_party/WebKit/Source/core/geometry/DOMMatrix.cpp b/third_party/WebKit/Source/core/geometry/DOMMatrix.cpp
index b87df838606e3c2599dc4e4769fcdb35e2ca82b0..cb27e0a711838f0c669267a7cefd93135d9e0318 100644
--- a/third_party/WebKit/Source/core/geometry/DOMMatrix.cpp
+++ b/third_party/WebKit/Source/core/geometry/DOMMatrix.cpp
@@ -6,13 +6,21 @@
 
 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;