Add a basic sky-element custom element

After this CL, you can use <sky-element> to describe custom elements. The
current iteration is very basic and is hardcoded to "example", but its a start.

This CL renames the |init| function to |_init| to prevent importers from
calling it directly. Also, we now pass the <script> element to |_init| to give
some context.

R=ojan@chromium.org, eseidel@chromium.org

Review URL: https://codereview.chromium.org/950493003

engine/core/html/parser/HTMLScriptRunner.cpp

@@ -115,8 +115,11 @@ void HTMLScriptRunner::executeLibrary(RefPtr<AbstractModule> module,
   // or script failures, etc.
   Microtask::performCheckpoint();
 
-  if (LocalFrame* frame = contextFrame(m_element.get()))
-    frame->dart().ExecuteLibraryInModule(module.get(), library->dart_value());
+  if (LocalFrame* frame = contextFrame(m_element.get())) {
+    frame->dart().ExecuteLibraryInModule(module.get(),
+                                         library->dart_value(),
+                                         m_element.get());
+  }
 
   advanceTo(StateCompleted);
   // We may be deleted at this point.

engine/core/script/dart_controller.cc

@@ -16,6 +16,7 @@
 #include "sky/engine/core/app/Module.h"
 #include "sky/engine/core/dom/Element.h"
 #include "sky/engine/core/frame/LocalFrame.h"
+#include "sky/engine/core/html/HTMLScriptElement.h"
 #include "sky/engine/core/html/imports/HTMLImport.h"
 #include "sky/engine/core/html/imports/HTMLImportChild.h"
 #include "sky/engine/core/loader/FrameLoaderClient.h"
@@ -29,6 +30,7 @@
 #include "sky/engine/tonic/dart_gc_controller.h"
 #include "sky/engine/tonic/dart_isolate_scope.h"
 #include "sky/engine/tonic/dart_state.h"
+#include "sky/engine/tonic/dart_wrappable.h"
 #include "sky/engine/wtf/text/TextPosition.h"
 
 namespace blink {
@@ -122,7 +124,8 @@ void DartController::LoadScriptInModule(
 }
 
 void DartController::ExecuteLibraryInModule(AbstractModule* module,
-                                            Dart_Handle library) {
+                                            Dart_Handle library,
+                                            HTMLScriptElement* script) {
   ASSERT(library);
   DCHECK(Dart_CurrentIsolate() == dart_state()->isolate());
   DartApiScope dart_api_scope;
@@ -130,16 +133,23 @@ void DartController::ExecuteLibraryInModule(AbstractModule* module,
   // Don't continue if we failed to load the module.
   if (LogIfError(Dart_FinalizeLoading(true)))
     return;
-  const char* name = module->isApplication() ? "main" : "init";
+  const char* name = module->isApplication() ? "main" : "_init";
 
   // main() is required, but init() is not:
   // TODO(rmacnak): Dart_LookupFunction won't find re-exports, etc.
   Dart_Handle entry = Dart_LookupFunction(library, ToDart(name));
-  if (!Dart_IsFunction(entry) && !module->isApplication())
+  if (module->isApplication()) {
+    LogIfError(Dart_Invoke(library, ToDart(name), 0, nullptr));
+    return;
+  }
+
+  if (!Dart_IsFunction(entry))
     return;
 
-  Dart_Handle result = Dart_Invoke(library, ToDart(name), 0, nullptr);
-  LogIfError(result);
+  Dart_Handle args[] = {
+    ToDart(script),
+  };
+  LogIfError(Dart_Invoke(library, ToDart(name), arraysize(args), args));
 }
 
 static void UnhandledExceptionCallback(Dart_Handle error) {

engine/core/script/dart_controller.h

@@ -16,8 +16,9 @@ namespace blink {
 class AbstractModule;
 class BuiltinSky;
 class DOMDartState;
-class Document;
 class DartValue;
+class Document;
+class HTMLScriptElement;
 
 class DartController {
  public:
@@ -33,7 +34,9 @@ class DartController {
                           const String& source,
                           const TextPosition& textPosition,
                           const LoadFinishedCallback& load_finished_callback);
-  void ExecuteLibraryInModule(AbstractModule* module, Dart_Handle library);
+  void ExecuteLibraryInModule(AbstractModule* module,
+                              Dart_Handle library,
+                              HTMLScriptElement* script);
 
   void ClearForClose();
   void CreateIsolateFor(Document* document);

examples/example-element/example-element.sky

@@ -0,0 +1,25 @@
+<!--
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+-->
+<import src="/sky/framework/sky-element.sky" />
+<sky-element>
+<template>
+  <style>
+    div {
+      height: 50px;
+      width: 50px;
+      background-color: green;
+    }
+  </style>
+  <div>Hi</div>
+</template>
+<script>
+@Tagname('example')
+class ExampleElement extends SkyElement {
+}
+
+_init(script) => register(script, ExampleElement);
+</script>
+</sky-element>

examples/example-element/index.sky

@@ -0,0 +1,16 @@
+<!--
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+-->
+<sky>
+  <import src="example-element.sky" />
+  <style>
+    example {
+      border: 1px solid blue;
+      width: 100px;
+      height: 100px;
+    }
+  </style>
+  <example />
+</sky>

framework/sky-element.sky

@@ -0,0 +1,85 @@
+<!--
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+-->
+<script>
+import "dart:mirrors";
+import "dart:sky";
+
+class _Registration {
+  Element template;
+  _Registration(this.template);
+}
+
+final Map<String, _Registration> _registery = new Map<String, _Registration>();
+
+class Tagname {
+  final String name;
+  const Tagname(this.name);
+}
+
+String _getTagName(Type type) {
+  return reflectClass(type).metadata.firstWhere(
+      (i) => i.reflectee is Tagname).reflectee.name;
+}
+
+abstract class SkyElement extends Element {
+  // Override these functions to receive lifecycle notifications.
+  void created() {}
+  void attached() {}
+  void detached() {}
+  void attributeChanged(String attrName, String oldValue, String newValue) {}
+  void shadowRootReady() {}
+
+  String get tagName => _getTagName(runtimeType);
+
+  // TODO(abarth): Rather than hard-coding "example" here, we should make the
+  // bindings read the |tagName| property of this object during construction.
+  SkyElement() : super("example") {
+    created();
+
+    // Invoke attributeChanged callback when element is first created too.
+    for (Attr attribute in getAttributes())
+      attributeChangedCallback(attribute.name, null, attribute.value);
+  }
+
+  attachedCallback() {
+    if (shadowRoot == null) {
+      var registration = _registery[tagName];
+      if (registration.template != null) {
+        ShadowRoot shadow = ensureShadowRoot();
+        var tree = registration.template.content.cloneNode(deep:true);
+        shadow.appendChild(tree);
+        shadowRootReady();
+      }
+    }
+    attached();
+  }
+
+  detachedCallback() {
+    detached();
+  }
+
+  attributeChangedCallback(name, oldValue, newValue) {
+    attributeChanged(name, oldValue, newValue);
+  }
+}
+
+void register(Element script, Type type) {
+  Element definition = script.parentNode;
+
+  if (definition.tagName != 'sky-element')
+    throw new UnsupportedError('register() calls must be inside a <sky-element>.');
+
+  ClassMirror mirror = reflectClass(type);
+  if (!mirror.isSubclassOf(reflectClass(SkyElement)))
+    throw new UnsupportedError('@Tagname can only be used on descendants of SkyElement');
+
+  String tagName = _getTagName(type);
+  Element template = definition.querySelector('template');
+
+  document.registerElement(tagName, type);
+  _registery[tagName] = new _Registration(template);
+}
+</script>

tests/modules/resources/multiple-scripts-child.sky

@@ -2,7 +2,7 @@
 <script>
 final String one = 'one';
 bool oneInit = false;
-void init() {
+void _init(_) {
     oneInit = true;
 }
 final conflict = 'one';
@@ -10,7 +10,7 @@ final conflict = 'one';
 <script>
 final String two = 'two';
 bool twoInit = false;
-void init() {
+void _init(_) {
     twoInit = true;
 }
 final conflict = 'two';

tests/modules/resources/with-dart-import.sky

@@ -6,7 +6,7 @@ class TestClass extends base.BaseClass {
 
 bool didInit = false;
 
-void init() {
+void _init(_) {
     didInit = (new TestClass() != null);
 }
 </script>

tests/resources/dump-as-markup.sky

@@ -3,7 +3,7 @@
 import "dart:sky";
 import "dart:sky.internals" as internals;
 
-void init() {
+void _init(_) {
   window.addEventListener('load', (_) {
     internals.notifyTestComplete(DomSerializer.serializeNode(document));
   });

tests/resources/dump-as-render-tree.sky

@@ -2,7 +2,7 @@
 import "dart:sky" as sky;
 import "dart:sky.internals" as internals;
 
-void init() {
+void _init(_) {
   sky.window.addEventListener('load', (_) =>
     internals.notifyTestComplete(internals.renderTreeAsText()));  
 }

tests/resources/dump-as-text.sky

@@ -6,7 +6,7 @@ void handleLoadEvent(event) {
   internals.notifyTestComplete(internals.contentAsText());
 }
 
-void init() {
+void _init(_) {
   sky.window.addEventListener('load', handleLoadEvent);
 }
 </script>