[WIP] Custom element upgrades

third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp

Index: third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
index 5a931d54967b5aac91082bd8081988fdefd640f1..20fc8ab190c51d2645ef91af5c6c11404d73a2c6 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
@@ -6,8 +6,12 @@
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/V8CustomElementsRegistry.h"
+#include "bindings/core/v8/V8Element.h"
 #include "bindings/core/v8/V8HiddenValue.h"
+#include "bindings/core/v8/V8ScriptRunner.h"
+#include "v8.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
@@ -153,6 +157,7 @@ ScriptCustomElementDefinition::ScriptCustomElementDefinition(
     const v8::Local<v8::Object>& constructor,
     const v8::Local<v8::Object>& prototype)
     : CustomElementDefinition(descriptor)
+    , m_scriptState(scriptState)
     , m_constructor(scriptState->isolate(), constructor)
     , m_prototype(scriptState->isolate(), prototype)
 {
@@ -163,6 +168,40 @@ ScriptCustomElementDefinition::ScriptCustomElementDefinition(
     m_prototype.setPhantom();
 }
 
+// https://html.spec.whatwg.org/multipage/scripting.html#upgrades
+bool ScriptCustomElementDefinition::upgrade(Element* element)
+{
+    if (!m_scriptState->contextIsValid())
+        return false;
+    ScriptState::Scope scope(m_scriptState.get());
+    v8::Isolate* isolate = m_scriptState->isolate();
+
+    // Step 5 says to rethrow the exception; but there is no one to
+    // catch it. The side effect is to report the error.
+    v8::TryCatch tryCatch(isolate);
+    tryCatch.SetVerbose(true);
+
+    ExecutionContext* executionContext = m_scriptState->getExecutionContext();
+    v8::Local<v8::Object> ctor = constructor(m_scriptState.get());
+    v8::Local<v8::Value> result;
+    if (!v8Call(V8ScriptRunner::callAsConstructor(
+        isolate,
+        ctor,
+        executionContext,
+        0,
+        nullptr),
+        result))
+        return false;
+
+    if (V8Element::toImplWithTypeCheck(isolate, result) != element) {
+        // TODO(dominicc): Throw InvalidStateError. Maybe Upgrade should
+        // take ExceptionState&?
+        return false;
+    }
+
+    return true;
+}
+
 v8::Local<v8::Object> ScriptCustomElementDefinition::constructor(
     ScriptState* scriptState) const
 {