IDL compiler: AudioBuffer interfaces

BUG=239771
R=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/131183002

git-svn-id: svn://svn.chromium.org/blink/trunk@165107 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/bindings/scripts/unstable/v8_interface.py

@@ -70,6 +70,10 @@ def generate_interface(interface):
         header_includes.update(v8_types.includes_for_type(parent_interface))
     extended_attributes = interface.extended_attributes
 
+    is_audio_buffer = inherits_interface(interface.name, 'AudioBuffer')
+    if is_audio_buffer:
+        includes.add('modules/webaudio/AudioBuffer.h')
+
     is_document = inherits_interface(interface.name, 'Document')
     if is_document:
         includes.update(['bindings/v8/ScriptController.h',
@@ -159,6 +163,7 @@ def generate_interface(interface):
             interface_length(interface, constructors + custom_constructors),
         'interface_name': interface.name,
         'is_active_dom_object': 'ActiveDOMObject' in extended_attributes,  # [ActiveDOMObject]
+        'is_audio_buffer': is_audio_buffer,
         'is_check_security': is_check_security,
         'is_constructor_call_with_document': has_extended_attribute_value(
             interface, 'ConstructorCallWith', 'Document'),  # [ConstructorCallWith=Document]

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

@@ -728,6 +728,16 @@ v8::Handle<v8::Object> {{v8_class}}::createWrapper(PassRefPtr<{{cpp_class}}> imp
     if (UNLIKELY(wrapper.IsEmpty()))
         return wrapper;
 
+    {% if is_audio_buffer %}
+    {# We only setDeallocationObservers on array buffers that are held by some
+       object in the V8 heap, not in the ArrayBuffer constructor itself.
+       This is because V8 GC only cares about memory it can free on GC, and
+       until the object is exposed to JavaScript, V8 GC doesn't affect it. #}
+    for (unsigned i = 0, n = impl->numberOfChannels(); i < n; i++) {
+        Float32Array* channelData = impl->getChannelData(i);
+        channelData->buffer()->setDeallocationObserver(V8ArrayBufferDeallocationObserver::instanceTemplate());
+    }
+    {% endif %}
     installPerContextEnabledProperties(wrapper, impl.get(), isolate);
     {% set wrapper_configuration = 'WrapperConfiguration::Dependent'
                                    if (has_visit_dom_wrapper or