bindings: Improves the speed perf of EventTarget.dispatchEvent.

third_party/WebKit/Source/bindings/templates/methods.cpp

 {% from 'conversions.cpp' import declare_enum_validation_variable, v8_value_to_local_cpp_value %}
 
 
 {##############################################################################}
 {% macro generate_method(method, world_suffix) %}
 {% filter conditional(method.conditional_string) %}
 {% if method.returns_promise and method.has_exception_state %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}Promise(const v8::FunctionCallbackInfo<v8::Value>& info, ExceptionState& exceptionState)
 {% else %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const v8::FunctionCallbackInfo<v8::Value>& info)
@@ skipping 10 matching lines @@
     }
     {% endif %}
     {% if not method.is_static %}
     {{cpp_class}}* impl = {{v8_class}}::toImpl(info.Holder());
     {% endif %}
     {% if method.is_custom_element_callbacks %}
     CustomElementProcessingStack::CallbackDeliveryScope deliveryScope;
     {% endif %}
     {# Security checks #}
     {% if method.is_check_security_for_receiver %}
+    {% if interface_name == 'EventTarget' %}
+    // Performance hack for EventTarget.  Checking whether it's a Window or not
+    // prior to the call to BindingSecurity::shouldAllowAccessTo increases 30%
+    // of speed performance on Android Nexus 7 as of Dec 2016.  ALWAYS_INLINE
+    // didn't work in this case.
+    if (LocalDOMWindow* window = impl->toDOMWindow()) {
+        if (!BindingSecurity::shouldAllowAccessTo(info.GetIsolate(), callingDOMWindow(info.GetIsolate()), window, exceptionState)) {
+            {% if not method.returns_promise %}
+            exceptionState.throwIfNeeded();
+            {% endif %}
+            return;
+        }
+    }
+    {% else %}{# interface_name == 'EventTarget' #}
     if (!BindingSecurity::shouldAllowAccessTo(info.GetIsolate(), callingDOMWindow(info.GetIsolate()), impl, exceptionState)) {
         {% if not method.returns_promise %}
         exceptionState.throwIfNeeded();
         {% endif %}
         return;
     }
+    {% endif %}{# interface_name == 'EventTarget' #}
     {% endif %}
     {% if method.is_check_security_for_return_value %}
     if (!BindingSecurity::shouldAllowAccessTo(info.GetIsolate(), callingDOMWindow(info.GetIsolate()), {{method.cpp_value}}, exceptionState)) {
         v8SetReturnValueNull(info);
         {% if not method.returns_promise %}
         exceptionState.throwIfNeeded();
         {% endif %}
         return;
     }
     {% endif %}
@@ skipping 645 matching lines @@
 {% filter runtime_enabled(method.overloads.runtime_enabled_function_all
                           if method.overloads else
                           method.runtime_enabled_function) %}
 const V8DOMConfiguration::MethodConfiguration {{method.name}}MethodConfiguration = {{method_configuration(method)}};
 V8DOMConfiguration::installMethod(isolate, v8::Local<v8::Object>(), prototypeObject, interfaceObject, defaultSignature, {{method.name}}MethodConfiguration);
 {% endfilter %}{# runtime_enabled() #}
 {% endfilter %}{# exposed() #}
 {% endfor %}
 {% endif %}
 {%- endmacro %}