JS errors thrown in private scripts should be reported to stderr in Debug builds

Source/bindings/templates/attributes.cpp

Index: Source/bindings/templates/attributes.cpp
diff --git a/Source/bindings/templates/attributes.cpp b/Source/bindings/templates/attributes.cpp
index 604751eb8b95f049be463eb773674b4601f346e6..5fecaac336977b82b4eaf9ff2df5e6f43143aaef 100644
--- a/Source/bindings/templates/attributes.cpp
+++ b/Source/bindings/templates/attributes.cpp
@@ -359,6 +359,9 @@ bool {{v8_class}}::PrivateScript::{{attribute.name}}AttributeGetter(LocalFrame*
 
     ExceptionState exceptionState(ExceptionState::GetterContext, "{{attribute.name}}", "{{cpp_class}}", scriptState->context()->Global(), scriptState->isolate());
     v8::TryCatch block;
+#ifndef NDEBUG
+    block.SetVerbose(true);
+#endif
     V8RethrowTryCatchScope rethrow(block);
     v8::Handle<v8::Value> v8Value = PrivateScriptRunner::runDOMAttributeGetter(scriptState, "{{cpp_class}}", "{{attribute.name}}", holder);
     if (block.HasCaught()) {
@@ -395,6 +398,9 @@ bool {{v8_class}}::PrivateScript::{{attribute.name}}AttributeSetter(LocalFrame*
 
     ExceptionState exceptionState(ExceptionState::SetterContext, "{{attribute.name}}", "{{cpp_class}}", scriptState->context()->Global(), scriptState->isolate());
     v8::TryCatch block;
+#ifndef NDEBUG
+    block.SetVerbose(true);
+#endif
     V8RethrowTryCatchScope rethrow(block);
     PrivateScriptRunner::runDOMAttributeSetter(scriptState, "{{cpp_class}}", "{{attribute.name}}", holder, {{attribute.private_script_cpp_value_to_v8_value}});
     if (block.HasCaught()) {