v8binding: Makes ToV8(window) work without a frame.

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

 // Copyright 2014 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/DOMWindow.h"
 
 #include <memory>
+
+#include "bindings/core/v8/WindowProxyManager.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/dom/SecurityContext.h"
 #include "core/events/MessageEvent.h"
 #include "core/frame/Frame.h"
 #include "core/frame/FrameClient.h"
 #include "core/frame/FrameConsole.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/Location.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
 #include "core/input/InputDeviceCapabilities.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/loader/MixedContentChecker.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
 #include "core/probe/CoreProbes.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "platform/weborigin/Suborigin.h"
 
 namespace blink {
 
-DOMWindow::DOMWindow(Frame& frame) : m_frame(frame), m_windowIsClosing(false) {}
+DOMWindow::DOMWindow(Frame& frame)
+    : m_frame(frame),
+      m_windowProxyManager(frame.getWindowProxyManager()),
+      m_windowIsClosing(false) {}
 
 DOMWindow::~DOMWindow() {
   // The frame must be disconnected before finalization.
   DCHECK(!m_frame);
 }
 
 v8::Local<v8::Object> DOMWindow::wrap(v8::Isolate*,
                                       v8::Local<v8::Object> creationContext) {
   LOG(FATAL) << "DOMWindow must never be wrapped with wrap method.  The "
                 "wrappers must be created at WindowProxy::createContext() and "
@@ skipping 365 matching lines @@
                  (toDocument(context)->domWindow() == opener());
   }
 
   // If we're a top level window, bring the window to the front.
   if (frame()->isMainFrame() && allowFocus)
     page->chromeClient().focus();
 
   page->focusController().focusDocumentView(frame(), true /* notifyEmbedder */);
 }
 
+v8::Local<v8::Object> DOMWindow::globalProxy(DOMWrapperWorld& world) {
+  return m_windowProxyManager->windowProxy(world)->globalProxyIfNotDetached();

[haraken, 2017/04/07 10:08:58]

So, are you planning to change this in the future to return a valid global proxy
even after the frame gets detached?

[Yuki, 2017/04/07 10:30:44]

Yes, I hope that I can make it someday.

+}
+
 InputDeviceCapabilitiesConstants* DOMWindow::getInputDeviceCapabilities() {
   if (!m_inputCapabilities)
     m_inputCapabilities = new InputDeviceCapabilitiesConstants;
   return m_inputCapabilities;
 }
 
 DEFINE_TRACE(DOMWindow) {
   visitor->trace(m_frame);
+  visitor->trace(m_windowProxyManager);
   visitor->trace(m_inputCapabilities);
   visitor->trace(m_location);
   EventTargetWithInlineData::trace(visitor);
 }
 
 }  // namespace blink