IDL: Drop value conversion (V8 -> C++) macros from generated code

Source/bindings/templates/union.cpp

Index: Source/bindings/templates/union.cpp
diff --git a/Source/bindings/templates/union.cpp b/Source/bindings/templates/union.cpp
index cd9c3692ade642b49edda25d197be29a7bb62923..2ccb8f612deb198a85d57dc4b7edf2041630ab7d 100644
--- a/Source/bindings/templates/union.cpp
+++ b/Source/bindings/templates/union.cpp
@@ -11,7 +11,7 @@
 if (V8{{member.type_name}}::hasInstance(v8Value, isolate)) {
     {{member.cpp_local_type}} cppValue = V8{{member.type_name}}::toImpl(v8::Local<v8::Object>::Cast(v8Value));
     impl.set{{member.type_name}}(cppValue);
-    return;
+    return true;
 }
 {% endmacro %}
 {% for filename in cpp_includes %}
@@ -64,10 +64,10 @@ void {{container.cpp_class}}::trace(Visitor* visitor)
 }
 
 {% endif %}
-void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value> v8Value, {{container.cpp_class}}& impl, ExceptionState& exceptionState)
+bool V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value> v8Value, {{container.cpp_class}}& impl, ExceptionState& exceptionState)
 {
     if (v8Value.IsEmpty())
-        return;
+        return true;
 
     {# The numbers in the following comments refer to the steps described in
        http://heycam.github.io/webidl/#es-union
@@ -99,7 +99,7 @@ void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value
         {% endif %}
         {{container.dictionary_type.v8_value_to_local_cpp_value}};
         impl.set{{container.dictionary_type.type_name}}(cppValue);
-        return;
+        return true;
     }
 
     {% endif %}
@@ -111,7 +111,7 @@ void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value
     if (v8Value->IsArray()) {
         {{container.array_or_sequence_type.v8_value_to_local_cpp_value}};
         impl.set{{container.array_or_sequence_type.type_name}}(cppValue);
-        return;
+        return true;
     }
 
     {% endif %}
@@ -121,7 +121,7 @@ void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value
     {# 14. Boolean #}
     if (v8Value->IsBoolean()) {
         impl.setBoolean(v8Value->ToBoolean()->Value());
-        return;
+        return true;
     }
 
     {% endif %}
@@ -130,7 +130,7 @@ void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value
     if (v8Value->IsNumber()) {
         {{container.numeric_type.v8_value_to_local_cpp_value}};
         impl.set{{container.numeric_type.type_name}}(cppValue);
-        return;
+        return true;
     }
 
     {% endif %}
@@ -142,11 +142,11 @@ void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value
         String string = cppValue;
         if (!({{container.string_type.enum_validation_expression}})) {
             exceptionState.throwTypeError("'" + string + "' is not a valid enum value.");
-            return;
+            return false;
         }
         {% endif %}
         impl.set{{container.string_type.type_name}}(cppValue);
-        return;
+        return true;
     }
 
     {# 17. Number (fallback) #}
@@ -154,19 +154,20 @@ void V8{{container.cpp_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value
     {
         {{container.numeric_type.v8_value_to_local_cpp_value}};
         impl.set{{container.numeric_type.type_name}}(cppValue);
-        return;
+        return true;
     }
 
     {# 18. Boolean (fallback) #}
     {% elif container.boolean_type %}
     {
-        impl.setBoolean(v8Value->ToBoolean()->Value());
-        return;
+        impl.setBoolean(v8Value->BooleanValue());
+        return true;
     }
 
     {% else %}
     {# 19. TypeError #}
     exceptionState.throwTypeError("The provided value is not of type '{{container.type_string}}'");
+    return false;
     {% endif %}
 }