Check for NULL after Frame lookup in findFrameByName

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 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 2472 matching lines @@
 }
 
 WebFrame* WebViewImpl::findFrameByName(
     const WebString& name, WebFrame* relativeToFrame)
 {
     // FIXME: Either this should only deal with WebLocalFrames or it should move to WebFrame.
     if (!relativeToFrame)
         relativeToFrame = mainFrame();
     Frame* frame = toWebLocalFrameImpl(relativeToFrame)->frame();
     frame = frame->tree().find(name);
-    if (!frame->isLocalFrame())
+    if (!frame || !frame->isLocalFrame())
         return 0;
     return WebLocalFrameImpl::fromFrame(toLocalFrame(frame));
 }
 
 WebFrame* WebViewImpl::focusedFrame()
 {
     return WebLocalFrameImpl::fromFrame(toLocalFrame(focusedWebCoreFrame()));
 }
 
 void WebViewImpl::setFocusedFrame(WebFrame* frame)
@@ skipping 1600 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink