Add a setting to allow window object reuse across a top-level initial navigation.

third_party/WebKit/Source/web/WebLocalFrameImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1538 matching lines @@
 }
 
 void WebLocalFrameImpl::initializeCoreFrame(FrameHost* host, FrameOwner* owner, const AtomicString& name, const AtomicString& uniqueName)
 {
     setCoreFrame(LocalFrame::create(m_frameLoaderClientImpl.get(), host, owner));
     frame()->tree().setPrecalculatedName(name, uniqueName);
     // We must call init() after m_frame is assigned because it is referenced
     // during init(). Note that this may dispatch JS events; the frame may be
     // detached after init() returns.
     frame()->init();
+    if (frame() && frame()->loader().stateMachine()->isDisplayingInitialEmptyDocument() && !parent() && !opener() && frame()->settings()->shouldReuseGlobalForUnownedMainFrame())
+        frame()->document()->getSecurityOrigin()->grantUniversalAccess();
 }
 
 RawPtr<LocalFrame> WebLocalFrameImpl::createChildFrame(const FrameLoadRequest& request,
     const AtomicString& name, HTMLFrameOwnerElement* ownerElement)
 {
     ASSERT(m_client);
     TRACE_EVENT0("blink", "WebLocalFrameImpl::createChildframe");
     WebTreeScopeType scope = frame()->document() == ownerElement->treeScope()
         ? WebTreeScopeType::Document
         : WebTreeScopeType::Shadow;
@@ skipping 601 matching lines @@
         return WebSandboxFlags::None;
     return static_cast<WebSandboxFlags>(frame()->loader().effectiveSandboxFlags());
 }
 
 void WebLocalFrameImpl::forceSandboxFlags(WebSandboxFlags flags)
 {
     frame()->loader().forceSandboxFlags(static_cast<SandboxFlags>(flags));
 }
 
 } // namespace blink