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

Source/bindings/templates/attributes.cpp

 {##############################################################################}
 {% macro attribute_getter(attribute, world_suffix) %}
 {% filter conditional(attribute.conditional_string) %}
 static void {{attribute.name}}AttributeGetter{{world_suffix}}(
 {%- if attribute.is_expose_js_accessors %}
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- else %}
 const v8::PropertyCallbackInfo<v8::Value>& info
 {%- endif %})
 {
@@ skipping 341 matching lines @@
         return false;
     ScriptState* scriptState = ScriptState::from(context);
     if (!scriptState->executionContext())
         return false;
 
     ScriptState::Scope scope(scriptState);
     v8::Handle<v8::Value> holder = toV8(holderImpl, scriptState->context()->Global(), scriptState->isolate());
 
     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()) {
         if (!PrivateScriptRunner::throwDOMExceptionInPrivateScriptIfNeeded(scriptState->isolate(), exceptionState, block.Exception())) {
             // FIXME: We should support exceptions other than DOM exceptions.
             RELEASE_ASSERT_NOT_REACHED();
         }
         return false;
     }
     {{attribute.private_script_v8_value_to_local_cpp_value}};
@@ skipping 16 matching lines @@
         return false;
     ScriptState* scriptState = ScriptState::from(context);
     if (!scriptState->executionContext())
         return false;
 
     ScriptState::Scope scope(scriptState);
     v8::Handle<v8::Value> holder = toV8(holderImpl, scriptState->context()->Global(), scriptState->isolate());
 
     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()) {
         if (!PrivateScriptRunner::throwDOMExceptionInPrivateScriptIfNeeded(scriptState->isolate(), exceptionState, block.Exception())) {
             // FIXME: We should support exceptions other than DOM exceptions.
             RELEASE_ASSERT_NOT_REACHED();
         }
         return false;
     }
     return true;
 }
 {% endmacro %}