custom-elements: Implement customElements.upgrade().

Intent-to-implement-and-ship: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/zCQe7UkR07w

Bug: 819482
Change-Id: I5645d5711d7fe1323992533e6c73593ba59d1bca
Reviewed-on: https://chromium-review.googlesource.com/1009450
Reviewed-by: Hayato Ito <hayato@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550513}

third_party/WebKit/LayoutTests/external/wpt/html/dom/interfaces.https-expected.txt

@@ -5456,6 +5456,8 @@ PASS CustomElementRegistry interface: operation get(DOMString)
 PASS Unscopable handled correctly for get(DOMString) on CustomElementRegistry
 PASS CustomElementRegistry interface: operation whenDefined(DOMString)
 PASS Unscopable handled correctly for whenDefined(DOMString) on CustomElementRegistry
+PASS CustomElementRegistry interface: operation upgrade(Node)
+PASS Unscopable handled correctly for upgrade(Node) on CustomElementRegistry
 PASS DataTransfer interface: existence and properties of interface object
 PASS DataTransfer interface object length
 PASS DataTransfer interface object name

third_party/WebKit/LayoutTests/external/wpt/interfaces/html.idl

@@ -1437,6 +1437,7 @@ interface CustomElementRegistry {
   [CEReactions] void define(DOMString name, Function constructor, optional ElementDefinitionOptions options);
   any get(DOMString name);
   Promise<void> whenDefined(DOMString name);
+  [CEReactions] void upgrade(Node root);
 };
 
 dictionary ElementDefinitionOptions {

third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -843,6 +843,7 @@ interface CustomElementRegistry
     method constructor
     method define
     method get
+    method upgrade
     method whenDefined
 interface CustomEvent : Event
     attribute @@toStringTag

third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt

@@ -1135,6 +1135,7 @@ interface CustomElementRegistry
     method constructor
     method define
     method get
+    method upgrade
     method whenDefined
 interface CustomEvent : Event
     attribute @@toStringTag

third_party/blink/renderer/core/html/custom/custom_element_registry.cc

@@ -11,7 +11,9 @@
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/dom/element.h"
 #include "third_party/blink/renderer/core/dom/element_definition_options.h"
+#include "third_party/blink/renderer/core/dom/element_traversal.h"
 #include "third_party/blink/renderer/core/dom/exception_code.h"
+#include "third_party/blink/renderer/core/dom/shadow_root.h"
 #include "third_party/blink/renderer/core/frame/local_dom_window.h"
 #include "third_party/blink/renderer/core/html/custom/ce_reactions_scope.h"
 #include "third_party/blink/renderer/core/html/custom/custom_element.h"
@@ -30,6 +32,25 @@
 
 namespace blink {
 
+namespace {
+
+void CollectUpgradeCandidateInNode(Node& root,
+                                   HeapVector<Member<Element>>& candidates) {
+  if (root.IsElementNode()) {
+    Element& root_element = ToElement(root);
+    if (root_element.GetCustomElementState() == CustomElementState::kUndefined)
+      candidates.push_back(root_element);
+    if (auto* shadow_root = root_element.GetShadowRoot()) {
+      if (shadow_root->GetType() != ShadowRootType::kUserAgent)
+        CollectUpgradeCandidateInNode(*shadow_root, candidates);
+    }
+  }
+  for (auto& element : Traversal<HTMLElement>::ChildrenOf(root))
+    CollectUpgradeCandidateInNode(element, candidates);
+}
+
+}  // anonymous namespace
+
 // Returns true if |name| is invalid.
 static bool ThrowIfInvalidName(const AtomicString& name,
                                ExceptionState& exception_state) {
@@ -337,4 +358,19 @@ void CustomElementRegistry::CollectCandidates(
   sorter.Sorted(elements, document);
 }
 
+// https://html.spec.whatwg.org/multipage/custom-elements.html#dom-customelementregistry-upgrade
+void CustomElementRegistry::upgrade(Node* root) {
+  DCHECK(root);
+
+  // 1. Let candidates be a list of all of root's shadow-including
+  // inclusive descendant elements, in tree order.
+  HeapVector<Member<Element>> candidates;
+  CollectUpgradeCandidateInNode(*root, candidates);
+
+  // 2. For each candidate of candidates, try to upgrade candidate.
+  for (auto& candidate : candidates) {
+    CustomElement::TryToUpgrade(candidate);
+  }
+}
+
 }  // namespace blink

third_party/blink/renderer/core/html/custom/custom_element_registry.h

@@ -64,6 +64,7 @@ class CORE_EXPORT CustomElementRegistry final : public ScriptWrappable {
   ScriptPromise whenDefined(ScriptState*,
                             const AtomicString& name,
                             ExceptionState&);
+  void upgrade(Node* root);
 
   void Entangle(V0CustomElementRegistrationContext*);
 

third_party/blink/renderer/core/html/custom/custom_element_registry.idl

@@ -6,4 +6,5 @@ interface CustomElementRegistry {
     [CallWith=ScriptState, CEReactions, CustomElementCallbacks, RaisesException, MeasureAs=CustomElementRegistryDefine] void define(DOMString name, Function constructor, optional ElementDefinitionOptions options);
     any get(DOMString name);
     [CallWith=ScriptState,RaisesException] Promise<void> whenDefined(DOMString name);
+    [CEReactions] void upgrade(Node root);
 };