[bindings] Implement an ExperimentEnabled IDL extended attribute.

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

 {% from 'conversions.cpp' import declare_enum_validation_variable, v8_value_to_local_cpp_value %}
-
+{% from 'api_experiment.cpp' import check_api_experiment %}
 
 {##############################################################################}
 {% macro attribute_getter(attribute, world_suffix) %}
 {% filter conditional(attribute.conditional_string) %}
 static void {{attribute.name}}AttributeGetter{{world_suffix}}(
 {%- if attribute.is_data_type_property %}
 const v8::PropertyCallbackInfo<v8::Value>& info
 {%- else %}
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- endif %})
 {
+    {% filter trim %}

[haraken, 2015/12/30 00:25:32]

Why is trim needed?

[Daniel Nishi, 2015/12/30 22:05:50]

I was having spacing issues because the macro was returning nothing sometimes,
causing the "| indent| to leave 4 whitespaces, which caused a presubmit error.

By adding an if-statement guard around the macro, I've avoided the problem and
fixed the whitespace issues that the trim caused.

+    {{check_api_experiment(attribute) | indent}}
+    {% endfilter %}
     {% if attribute.is_reflect and not attribute.is_url
           and attribute.idl_type == 'DOMString' and is_node
           and not attribute.is_implemented_in_private_script %}
     {% set cpp_class, v8_class = 'Element', 'V8Element' %}
     {% endif %}
     {# holder #}
     {% if not attribute.is_static %}
     {% if attribute.is_lenient_this %}
     {# Make sure that info.Holder() really points to an instance if [LenientThis]. #}
     if (!{{v8_class}}::hasInstance(info.Holder(), info.GetIsolate()))
@@ skipping 147 matching lines @@
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- endif %})
 {
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "DOMGetter");
     {% if attribute.deprecate_as %}
     UseCounter::countDeprecationIfNotPrivateScript(info.GetIsolate(), callingExecutionContext(info.GetIsolate()), UseCounter::{{attribute.deprecate_as}});
     {% endif %}
     {% if attribute.measure_as %}
     UseCounter::countIfNotPrivateScript(info.GetIsolate(), callingExecutionContext(info.GetIsolate()), UseCounter::{{attribute.measure_as('AttributeGetter')}});
     {% endif %}
+    {% filter trim %}
+    {{check_api_experiment(attribute) | indent}}
+    {% endfilter %}
     {% if world_suffix in attribute.activity_logging_world_list_for_getter %}
     ScriptState* scriptState = ScriptState::from(info.GetIsolate()->GetCurrentContext());
     V8PerContextData* contextData = scriptState->perContextData();
     {% if attribute.activity_logging_world_check %}
     if (scriptState->world().isIsolatedWorld() && contextData && contextData->activityLogger())
     {% else %}
     if (contextData && contextData->activityLogger())
     {% endif %}
         contextData->activityLogger()->logGetter("{{interface_name}}.{{attribute.name}}");
     {% endif %}
@@ skipping 13 matching lines @@
 {% filter conditional(attribute.conditional_string) %}
 static void {{attribute.name}}ConstructorGetterCallback{{world_suffix}}(v8::Local<v8::Name> property, const v8::PropertyCallbackInfo<v8::Value>& info)
 {
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "DOMGetter");
     {% if attribute.deprecate_as %}
     UseCounter::countDeprecationIfNotPrivateScript(info.GetIsolate(), callingExecutionContext(info.GetIsolate()), UseCounter::{{attribute.deprecate_as}});
     {% endif %}
     {% if attribute.measure_as %}
     UseCounter::countIfNotPrivateScript(info.GetIsolate(), callingExecutionContext(info.GetIsolate()), UseCounter::{{attribute.measure_as('ConstructorGetter')}});
     {% endif %}
+    {% filter trim %}
+    {{check_api_experiment(attribute) | indent}}
+    {% endfilter %}
     v8ConstructorAttributeGetter(property, info);
     TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8Execution");
 }
 {% endfilter %}
 {% endmacro %}
 
 
 {##############################################################################}
 {% macro attribute_setter(attribute, world_suffix) %}
 {% filter conditional(attribute.conditional_string) %}
@@ skipping 187 matching lines @@
         return false;
     ScriptState* scriptStateInUserScript = ScriptState::forMainWorld(frame);
     if (!scriptState->contextIsValid())
         return false;
 
     ScriptState::Scope scope(scriptState);
     v8::Local<v8::Value> holder = toV8(holderImpl, scriptState->context()->Global(), scriptState->isolate());
     if (holder.IsEmpty())
         return false;
 
+    {% filter trim %}
+    {{check_api_experiment(attribute) | indent}}
+    {% endfilter %}
+
     ExceptionState exceptionState(ExceptionState::GetterContext, "{{attribute.name}}", "{{cpp_class}}", scriptState->context()->Global(), scriptState->isolate());
     v8::Local<v8::Value> v8Value = PrivateScriptRunner::runDOMAttributeGetter(scriptState, scriptStateInUserScript, "{{cpp_class}}", "{{attribute.name}}", holder);
     if (v8Value.IsEmpty())
         return false;
     {{v8_value_to_local_cpp_value(attribute.private_script_v8_value_to_local_cpp_value) | indent}}
     RELEASE_ASSERT(!exceptionState.hadException());
     *result = cppValue;
     return true;
 }
 {% endmacro %}
@@ skipping 75 matching lines @@
        setter_callback_for_main_world,
        wrapper_type_info,
        access_control,
        property_attribute,
        only_exposed_to_private_script,
        property_location(attribute),
        holder_check,
    ] %}
 {{'{'}}{{attribute_configuration_list | join(', ')}}{{'}'}}
 {%- endmacro %}