[Origin Trials] Install origin trial bindings on V8 context conditionally

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 abd7ca3320ecfc0a6755172837a200020ebe2a8a..adedcb304019b5f64999385797f4e12c87a75931 100644
--- a/third_party/WebKit/Source/bindings/templates/interface_base.cpp
+++ b/third_party/WebKit/Source/bindings/templates/interface_base.cpp
@@ -365,6 +365,35 @@ static void install{{v8_class}}Template(v8::Isolate* isolate, const DOMWrapperWo
 {% endif %}{# not is_array_buffer_or_view #}
 {% endblock %}
 {##############################################################################}
+{% block origin_trials %}
+{% from 'attributes.cpp' import attribute_configuration with context %}
+{% for group in attributes|origin_trial_enabled_attributes|groupby('origin_trial_feature_name') %}{{newline}}
+void {{v8_class_or_partial}}::install{{group.grouper}}(ScriptState* scriptState, v8::Local<v8::Object> instance)
+{
+    v8::Local<v8::Object> prototype = instance->GetPrototype()->ToObject(scriptState->isolate());
+    {% for attribute in group.list | unique_by('name') | sort %}
+    {% if attribute.is_data_type_property %}
+    const V8DOMConfiguration::AttributeConfiguration attribute{{attribute.name}}Configuration = \
+        {{attribute_configuration(attribute)}};
+    V8DOMConfiguration::installAttribute(scriptState->isolate(), scriptState->world(), instance, prototype, attribute{{attribute.name}}Configuration);

[Yuki, 2016/05/31 05:05:32]

Note for the binding team: We may want to rename installAttribute to
installInterfaceObject or something like that.

+    {% else %}
+    v8::Local<v8::Signature> signature;
+    // This parameter is required for installAccessor, to install static
+    // attributes on existing interfaces. This is not currently supported in
+    // origin trials, and this parameter is unused by installAccessor. (An
+    // assertion in the bindings generation code ensures this.)
+    // TODO(iclelland): Replace this with the actual interface, to allow origin
+    // trials on static attributes. (crbug.com/614352)

[Yuki, 2016/05/31 05:05:32]

I don't understand this comment.

Are you trying to install a static attribute?  Then, you really need an
interface object where the static attribute is going to be installed. 
Otherwise, it's meaningless.

If you don't have any static attribute yet.  Then, you don't need to create a
function object as an interface object.  Just use an empty handle, passing
v8::Local<v8::Function>() should work.

If you need an interface object, then you can use
perIsolateData->construtorForType().

[iclelland, 2016/05/31 05:34:52]

No. 
Yes, that's what I was trying to say with the comment. I was trying to explain
why I was generating a useless function object to pass to installAccessor.
That's definitely cleaner than what I was doing. I've switch to that (and
removed the unfortunately confusing comment.) Thanks.

+    v8::Local<v8::Function> interface = v8::Function::New(scriptState->context(), nullptr).ToLocalChecked();
+    const V8DOMConfiguration::AccessorConfiguration accessor{{attribute.name}}Configuration = \
+        {{attribute_configuration(attribute)}};
+    V8DOMConfiguration::installAccessor(scriptState->isolate(), scriptState->world(), instance, prototype, interface, signature, accessor{{attribute.name}}Configuration);
+    {% endif %}
+    {% endfor %}
+}
+{% endfor %}
+{% endblock %}
+{##############################################################################}
 {% block get_dom_template %}{% endblock %}
 {% block get_dom_template_for_named_properties_object %}{% endblock %}
 {% block has_instance %}{% endblock %}