Oilpan: fix (MSVC) build after r183241.

Source/web/WebFrame.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 "public/web/WebFrame.h"
 
 #include "core/frame/RemoteFrame.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "platform/UserGestureIndicator.h"
@@ skipping 230 matching lines @@
 void WebFrame::traceFrames(Visitor* visitor, WebFrame* frame)
 {
     ASSERT(frame);
     traceFrame(visitor, frame->m_parent);
     for (WebFrame* child = frame->firstChild(); child; child = child->nextSibling())
         traceFrame(visitor, child);
     // m_opener is a weak reference.
     frame->m_openedFrameTracker->traceFrames(visitor);
 }
 
-bool WebFrame::isAlive(Visitor* visitor, WebFrame* frame)
+bool WebFrame::isFrameAlive(Visitor* visitor, const WebFrame* frame)
 {
     if (!frame)
         return true;
 
     if (frame->isWebLocalFrame())
         return visitor->isAlive(toWebLocalFrameImpl(frame));
 
     return visitor->isAlive(toWebRemoteFrameImpl(frame));
 }
 
 void WebFrame::clearWeakFrames(Visitor* visitor)
 {
-    if (!isAlive(visitor, m_opener))
+    if (!isFrameAlive(visitor, m_opener))
         m_opener = nullptr;
 }
 #endif
 
 } // namespace blink