[bindings] Implement an ExperimentEnabled IDL extended attribute.

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

Index: third_party/WebKit/Source/bindings/templates/interface_base.cpp
diff --git a/third_party/WebKit/Source/bindings/templates/interface_base.cpp b/third_party/WebKit/Source/bindings/templates/interface_base.cpp
index 22102d8796868d8ad8c07e5265562e0feb5022a6..b7c0b601af447556d656108112b01887c7525a89 100644
--- a/third_party/WebKit/Source/bindings/templates/interface_base.cpp
+++ b/third_party/WebKit/Source/bindings/templates/interface_base.cpp
@@ -300,10 +300,20 @@ static void install{{v8_class}}Template(v8::Local<v8::FunctionTemplate> function
     {% if runtime_enabled_function %}
     if (!{{runtime_enabled_function}}())
         defaultSignature = V8DOMConfiguration::installDOMClassTemplate(isolate, functionTemplate, "{{interface_name}}", {{parent_template}}, {{v8_class}}::internalFieldCount, 0, 0, 0, 0, 0, 0);
-    else
+    else {
     {% endif %}
     {% set runtime_enabled_indent = 4 if runtime_enabled_function else 0 %}
     {% filter indent(runtime_enabled_indent, true) %}
+    {% if api_experiment_name %}
+    ExecutionContext* ec = currentExecutionContext(isolate);
+    ALLOW_UNUSED_LOCAL(ec);
+    if (!Experiments::isApiEnabledWithoutMessage(ec, "{{api_experiment_name}}")) {
+        defaultSignature = V8DOMConfiguration::installDOMClassTemplate(isolate, functionTemplate, "{{interface_name}}", {{parent_template}}, {{v8_class}}::internalFieldCount, 0, 0, 0, 0, 0, 0);
+    }
+    else
+    {% endif %}
+    {% set api_experiment_enabled_indent = 4 if api_experiment_name else runtime_enabled_indent %}
+    {% filter indent(api_experiment_enabled_indent, true) %}
     defaultSignature = V8DOMConfiguration::installDOMClassTemplate(isolate, functionTemplate, "{{interface_name}}", {{parent_template}}, {{v8_class}}::internalFieldCount,
         {# Test needed as size 0 arrays definitions are not allowed per standard
            (so objects have distinct addresses), which is enforced by MSVC.
@@ -326,7 +336,12 @@ static void install{{v8_class}}Template(v8::Local<v8::FunctionTemplate> function
         {{attributes_name}}, {{attributes_length}},
         {{accessors_name}}, {{accessors_length}},
         {{methods_name}}, {{methods_length}});
-    {% endfilter %}
+    {% endfilter %}{# api_experiment_enabled_indent #}
+    {% endfilter %}{# runtime_enabled_indent #}
+    {% if runtime_enabled_function %}
+
+    }
+    {% endif %}
 
     {% if constructors or has_custom_constructor or has_event_constructor %}
     functionTemplate->SetCallHandler({{v8_class}}::constructorCallback);
@@ -353,6 +368,7 @@ static void install{{v8_class}}Template(v8::Local<v8::FunctionTemplate> function
     {% endfilter %}{# runtime_enabled() #}
     {% endif %}
     {% set runtime_enabled_features = dict() %}
+    {% set api_experiment_enabled_features = dict() %}
     {% for attribute in attributes
        if attribute.runtime_enabled_function and
           not attribute.exposed_test %}
@@ -394,8 +410,10 @@ static void install{{v8_class}}Template(v8::Local<v8::FunctionTemplate> function
     {% if iterator_method %}
     {% filter exposed(iterator_method.exposed_test) %}
     {% filter runtime_enabled(iterator_method.runtime_enabled_function) %}
+    {% filter api_experiment_enabled(iterator_method.api_experiment_name) %}
     const V8DOMConfiguration::SymbolKeyedMethodConfiguration symbolKeyedIteratorConfiguration = { v8::Symbol::GetIterator, {{cpp_class_or_partial}}V8Internal::iteratorMethodCallback, 0, v8::DontDelete, V8DOMConfiguration::ExposedToAllScripts, V8DOMConfiguration::OnPrototype };
     V8DOMConfiguration::installMethod(isolate, prototypeTemplate, defaultSignature, symbolKeyedIteratorConfiguration);
+    {% endfilter %}{# api_experiment_enabled() #}
     {% endfilter %}{# runtime_enabled() #}
     {% endfilter %}{# exposed() #}
     {% endif %}
@@ -416,12 +434,16 @@ static void install{{v8_class}}Template(v8::Local<v8::FunctionTemplate> function
     {% filter runtime_enabled(method.overloads.runtime_enabled_function_all
                               if method.overloads else
                               method.runtime_enabled_function) %}
+    {% filter api_experiment_enabled(method.overloads.api_experiment_name_all
+                              if method.overloads else
+                              method.api_experiment_name) %}
     {% if method.is_do_not_check_security %}
     {{install_do_not_check_security_method(method, '', 'instanceTemplate', 'prototypeTemplate') | indent}}
     {% else %}{# is_do_not_check_security #}
     {% set signature = 'v8::Local<v8::Signature>()' if method.is_do_not_check_signature else 'defaultSignature' %}
     {{install_custom_signature(method, 'instanceTemplate', 'prototypeTemplate', 'functionTemplate', signature) | indent}}
     {% endif %}{# is_do_not_check_security #}
+    {% endfilter %}{# api_experiment_enabled() #}
     {% endfilter %}{# runtime_enabled() #}
     {% endfilter %}{# exposed() #}
     {% endfilter %}{# conditional() #}