Make browsing context keywords case-insensitive.

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1569 matching lines @@
     // Because FrameTree::find() returns true for empty strings, we must check
     // for empty frame names.  Otherwise, illegitimate window.open() calls with
     // no name will pass right through the popup blocker.
     if (frameName.isEmpty() || !frame()->tree().find(frameName))
       return nullptr;
   }
 
   // Get the target frame for the special cases of _top and _parent.
   // In those cases, we schedule a location change right now and return early.
   Frame* targetFrame = nullptr;
-  if (frameName == "_top") {
+  if (equalIgnoringASCIICase(frameName, "_top")) {
     targetFrame = frame()->tree().top();
-  } else if (frameName == "_parent") {
+  } else if (equalIgnoringASCIICase(frameName, "_parent")) {
     if (Frame* parent = frame()->tree().parent())
       targetFrame = parent;
     else
       targetFrame = frame();
   }
 
   if (targetFrame) {
     if (!activeDocument->frame() ||
         !activeDocument->frame()->canNavigate(*targetFrame))
       return nullptr;
@@ skipping 40 matching lines @@
   DOMWindow::trace(visitor);
   Supplementable<LocalDOMWindow>::trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(LocalDOMWindow) {
   visitor->traceWrappers(m_customElements);
   DOMWindow::traceWrappers(visitor);
 }
 
 }  // namespace blink