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

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

Index: third_party/WebKit/Source/core/frame/DOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMWindow.cpp b/third_party/WebKit/Source/core/frame/DOMWindow.cpp
index fa9d7601038597b8aaacb573e1d15af92a3308b4..99a248abfd63f422e93c053c34570d26524f9574 100644
--- a/third_party/WebKit/Source/core/frame/DOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/DOMWindow.cpp
@@ -5,6 +5,8 @@
 #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"
@@ -29,7 +31,10 @@
 
 namespace blink {
 
-DOMWindow::DOMWindow(Frame& frame) : frame_(frame), window_is_closing_(false) {}
+DOMWindow::DOMWindow(Frame& frame)
+    : frame_(frame),
+      window_proxy_manager_(frame.GetWindowProxyManager()),
+      window_is_closing_(false) {}
 
 DOMWindow::~DOMWindow() {
   // The frame must be disconnected before finalization.
@@ -420,6 +425,11 @@ void DOMWindow::focus(ExecutionContext* context) {
                                                true /* notifyEmbedder */);
 }
 
+v8::Local<v8::Object> DOMWindow::GlobalProxy(DOMWrapperWorld& world) {
+  return window_proxy_manager_->GetWindowProxy(world)
+      ->GlobalProxyIfNotDetached();

[haraken, 2017/04/14 18:51:50]

Shall we add a TODO and mention that this should return a valid global proxy
even after the frame gets detached?

[Yuki, 2017/04/17 07:15:26]

Done.

+}
+
 InputDeviceCapabilitiesConstants* DOMWindow::GetInputDeviceCapabilities() {
   if (!input_capabilities_)
     input_capabilities_ = new InputDeviceCapabilitiesConstants;
@@ -428,6 +438,7 @@ InputDeviceCapabilitiesConstants* DOMWindow::GetInputDeviceCapabilities() {
 
 DEFINE_TRACE(DOMWindow) {
   visitor->Trace(frame_);
+  visitor->Trace(window_proxy_manager_);
   visitor->Trace(input_capabilities_);
   visitor->Trace(location_);
   EventTargetWithInlineData::Trace(visitor);