Initial stub version of Async Clipboard API

third_party/WebKit/Source/core/frame/NavigatorClipboard.cpp

Index: third_party/WebKit/Source/core/frame/NavigatorClipboard.cpp
diff --git a/third_party/WebKit/Source/core/frame/NavigatorClipboard.cpp b/third_party/WebKit/Source/core/frame/NavigatorClipboard.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7743a81881ccf2e84023b497c8d4553409febe26
--- /dev/null
+++ b/third_party/WebKit/Source/core/frame/NavigatorClipboard.cpp
@@ -0,0 +1,44 @@
+// Copyright 2017 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/frame/NavigatorClipboard.h"
+
+#include "core/clipboard/Clipboard.h"
+#include "core/dom/Document.h"
+#include "core/frame/LocalFrame.h"
+
+namespace blink {
+
+Clipboard* NavigatorClipboard::clipboard(ScriptState* scriptState,
+                                         Navigator& navigator) {
+  NavigatorClipboard* supplement = static_cast<NavigatorClipboard*>(
+      Supplement<Navigator>::from(navigator, supplementName()));
+  if (!supplement) {
+    supplement = new NavigatorClipboard(navigator);
+    provideTo(navigator, supplementName(), supplement);
+  }
+
+  if (!supplement->m_clipboard) {
+    supplement->m_clipboard =
+        new Clipboard(supplement->supplementable()->frame()
+                          ? supplement->supplementable()->frame()->document()
+                          : nullptr);
+  }
+
+  return supplement->m_clipboard;
+}
+
+DEFINE_TRACE(NavigatorClipboard) {
+  visitor->trace(m_clipboard);
+  Supplement<Navigator>::trace(visitor);
+}
+
+NavigatorClipboard::NavigatorClipboard(Navigator& navigator)
+    : Supplement<Navigator>(navigator) {}
+
+const char* NavigatorClipboard::supplementName() {
+  return "NavigatorClipboard";
+}
+
+}  // namespace blink