Move Location to DOMWindow

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 "config.h"
 #include "core/frame/DOMWindow.h"
 
 #include "core/dom/SecurityContext.h"
 #include "core/frame/Frame.h"
 #include "core/frame/FrameClient.h"
+#include "core/frame/Location.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/SecurityOrigin.h"
 
 namespace blink {
 
+DOMWindow::~DOMWindow()
+{
+}
+
+Location* DOMWindow::location() const
+{
+    if (!m_location)
+        m_location = Location::create(frame());
+    return m_location.get();
+}
+
 bool DOMWindow::closed() const
 {
     return !frame() || !frame()->host();
 }
 
 unsigned DOMWindow::length() const
 {
     return frame() ? frame()->tree().scopedChildCount() : 0;
 }
 
@@ skipping 59 matching lines @@
             return false;
 
         // FIXME: The name canAccess seems to be a roundabout way to ask "can execute script".
         // Can we name the SecurityOrigin function better to make this more clear?
         if (callingWindow.frame()->securityContext()->securityOrigin()->canAccess(frame()->securityContext()->securityOrigin()))
             return false;
     }
     return true;
 }
 
+void DOMWindow::reset()
+{
+    // Location needs to be reset manually because it doesn't inherit from DOMWindowProperty.

[haraken, 2015/02/03 00:56:09]

I'm just curious, but why can't Location inherit from DOMWindowProperty?

[dcheng, 2015/02/03 08:22:54]

Location was the only DOMWindowProperty that needed to support both LocalFrame
and RemoteFrame. All other properties are LocalFrame only.

Two other approaches were explored:
- Make DOMWindowProperty support a generic Frame. However, all subclasses of
DOMWindowProperty only work properly with LocalFrame, so we end up losing a lot
of type safety.
- Make DOMWindowProperty and LocalDOMWindowProperty. It was also a big cognitive
overhead--we will have DOMWindowProperty and LocalDOMWindowProperty, but no
RemoteDOMWindowProperty. It didn't seem to gain much in simplicity.

In the end, it seemed better to just special-case Location, since it is unique
in being accessible cross-origin.

[haraken, 2015/02/03 08:24:09]

Thanks, sounds reasonable to me.

+    m_location->reset();
+    m_location = nullptr;
+}
+
 } // namespace blink