Synchronize is-valid flag upon programmatic clearing of file.value

Source/core/html/forms/FileInputType.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 182 matching lines @@
     // HTML5 tells us that we're supposed to use this goofy value for
     // file input controls. Historically, browsers revealed the real
     // file path, but that's a privacy problem. Code on the web
     // decided to try to parse the value by looking for backslashes
     // (because that's what Windows file paths use). To be compatible
     // with that code, we make up a fake path for the file.
     value = "C:\\fakepath\\" + m_fileList->item(0)->name();
     return true;
 }
 
-void FileInputType::setValue(const String&, bool, TextFieldEventBehavior)
+void FileInputType::setValue(const String&, bool valueChanged, TextFieldEventBehavior)
 {
+    if (!valueChanged)
+        return;
+
     m_fileList->clear();
     element().setNeedsStyleRecalc();
+    element().setNeedsValidityCheck();
 }
 
 PassRefPtr<FileList> FileInputType::createFileList(const Vector<FileChooserFileInfo>& files) const
 {
     RefPtr<FileList> fileList(FileList::create());
     size_t size = files.size();
 
     // If a directory is being selected, the UI allows a directory to be chosen
     // and the paths provided here share a root directory somewhere up the tree;
     // we want to store only the relative paths from that point.
@@ skipping 155 matching lines @@
     StringBuilder names;
     for (size_t i = 0; i < listSize; ++i) {
         names.append(fileList->item(i)->name());
         if (i != listSize - 1)
             names.append('\n');
     }
     return names.toString();
 }
 
 } // namespace WebCore