Clear the custom element's reaction queue if upgrade fails.

third_party/WebKit/Source/core/dom/custom/CustomElementDefinitionTest.cpp

+// Copyright 2016 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.
+
+#include "core/dom/custom/CustomElementDefinition.h"
+
+#include "core/dom/Node.h"  // CustomElementState
+#include "core/dom/custom/CEReactionsScope.h"
+#include "core/dom/custom/CustomElementDescriptor.h"
+#include "core/dom/custom/CustomElementReactionTestHelpers.h"
+#include "core/dom/custom/CustomElementTestHelpers.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+namespace {
+
+class ConstructorFails : public TestCustomElementDefinition {
+  WTF_MAKE_NONCOPYABLE(ConstructorFails);
+
+ public:
+  ConstructorFails(const CustomElementDescriptor& descriptor)
+      : TestCustomElementDefinition(descriptor) {}
+  ~ConstructorFails() override = default;
+  bool runConstructor(Element*) override { return false; }
+};
+
+}  // namespace
+
+TEST(CustomElementDefinitionTest, upgrade_clearsReactionQueueOnFailure) {
+  Element* element = CreateElement("a-a");
+  EXPECT_EQ(CustomElementState::Undefined, element->getCustomElementState())
+      << "sanity check: this element should be ready to upgrade";
+  {
+    CEReactionsScope reactions;
+    reactions.enqueueToCurrentQueue(
+        element, new TestReaction({new Unreached(
+                     "upgrade failure should clear the reaction queue")}));
+    ConstructorFails definition(CustomElementDescriptor("a-a", "a-a"));
+    definition.upgrade(element);
+  }
+  EXPECT_EQ(CustomElementState::Failed, element->getCustomElementState())
+      << "failing to construct should have set the 'failed' element state";
+}
+
+TEST(CustomElementDefinitionTest,
+     upgrade_clearsReactionQueueOnFailure_backupStack) {
+  Element* element = CreateElement("a-a");
+  EXPECT_EQ(CustomElementState::Undefined, element->getCustomElementState())
+      << "sanity check: this element should be ready to upgrade";
+  ResetCustomElementReactionStackForTest resetReactionStack;
+  resetReactionStack.stack().enqueueToBackupQueue(
+      element, new TestReaction({new Unreached(
+                   "upgrade failure should clear the reaction queue")}));
+  ConstructorFails definition(CustomElementDescriptor("a-a", "a-a"));
+  definition.upgrade(element);
+  EXPECT_EQ(CustomElementState::Failed, element->getCustomElementState())
+      << "failing to construct should have set the 'failed' element state";
+}
+
+}  // namespace blink