[bindings] Implement an ExperimentEnabled IDL extended attribute.

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

Index: third_party/WebKit/Source/bindings/templates/methods.cpp
diff --git a/third_party/WebKit/Source/bindings/templates/methods.cpp b/third_party/WebKit/Source/bindings/templates/methods.cpp
index c9295cdb161dd59f47fef4cb27ac0742c9f17d09..ee656f36e1126c0a73840cdf8093b1f76c8d072f 100644
--- a/third_party/WebKit/Source/bindings/templates/methods.cpp
+++ b/third_party/WebKit/Source/bindings/templates/methods.cpp
@@ -366,7 +366,7 @@ createMinimumArityTypeErrorForMethod(info.GetIsolate(), "{{method.name}}", "{{in
 static int {{overloads.name}}MethodLength()
 {
     {% for length, runtime_enabled_functions in overloads.runtime_determined_lengths %}
-    {% for runtime_enabled_function in runtime_enabled_functions %}
+{% for runtime_enabled_function in runtime_enabled_functions %}
     {% filter runtime_enabled(runtime_enabled_function) %}
     return {{length}};
     {% endfilter %}
@@ -417,6 +417,8 @@ static void {{overloads.name}}Method{{world_suffix}}(const v8::FunctionCallbackI
         {% if method.visible %}
         {% filter runtime_enabled(not overloads.runtime_enabled_function_all and
                                   method.runtime_enabled_function) %}
+        {% filter api_experiment_enabled(not overloads.api_experiment_name_all and
+                                     method.api_experiment_name) %}

[haraken, 2015/12/18 02:35:51]

Ditto. Want to avoid the code duplication.

[Daniel Nishi, 2015/12/18 05:11:42]

Hm. The (not x_all and x) logic on this particular one is dense enough that I'm
not sure I can solve the duplication without overcomplicating it. Unlike the
other two, it doesn't share the method.overloads check.

[haraken, 2015/12/18 05:20:03]

BTW, do we really need to differentiate [APIExperimentEnabled] from
[RuntimeEnabled]? From the perspective that it is a mechanism to conditionally
enable DOM features, these two are the same thing.

Just an idea but would it be possible to implement the API-experiment on top of
the existing mechanism of RuntimeEnabledFeatures? For example, you can introduce
status=api-experiment to RuntimeEnabledFeature.in.

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

         if ({{test}}) {
             {% if method.measure_as and not overloads.measure_all_as %}
             UseCounter::countIfNotPrivateScript(info.GetIsolate(), callingExecutionContext(info.GetIsolate()), UseCounter::{{method.measure_as('Method')}});
@@ -428,6 +430,7 @@ static void {{overloads.name}}Method{{world_suffix}}(const v8::FunctionCallbackI
             return;
         }
         {% endfilter %}
+        {% endfilter %}
         {% endif %}
         {% endfor %}
         break;
@@ -707,8 +710,12 @@ ASSERT(executionContext);
 {% 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) %}

[haraken, 2015/12/18 02:35:51]

Ditto. Want to avoid the code duplication.

[Daniel Nishi, 2015/12/18 05:11:42]

Done in the same manner w/ sharing the method.overloads logic and sharing logic
between the filters.

 const V8DOMConfiguration::MethodConfiguration {{method.name}}MethodConfiguration = {{method_configuration(method)}};
 V8DOMConfiguration::installMethod(isolate, v8::Local<v8::Object>(), prototypeObject, interfaceObject, defaultSignature, {{method.name}}MethodConfiguration);
+{% endfilter %}{# api_experiment_enabled() #}
 {% endfilter %}{# runtime_enabled() #}
 {% endfilter %}{# exposed() #}
 {% endfor %}