Merge 94045 - REGRESSION(r88115): Disabling a file upload control causes an endless busyloop.

Source/WebCore/rendering/RenderFileUploadControl.cpp

 /*
  * Copyright (C) 2006, 2007 Apple 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 45 matching lines @@
 
 RenderFileUploadControl::~RenderFileUploadControl()
 {
 }
 
 void RenderFileUploadControl::updateFromElement()
 {
     HTMLInputElement* input = static_cast<HTMLInputElement*>(node());
     ASSERT(input->isFileUpload());
 
-    if (HTMLInputElement* button = uploadButton())
-        button->setDisabled(!theme()->isEnabled(this));
+    if (HTMLInputElement* button = uploadButton()) {
+        bool newDisabled = !theme()->isEnabled(this);
+        // We should avoid to call HTMLFormControlElement::setDisabled() as
+        // possible because setAttribute() in setDisabled() can cause style
+        // recalculation, and HTMLFormControlElement::recalcStyle() calls
+        // updateFromElement() eventually.
+        if (button->disabled() != newDisabled)
+            button->setDisabled(newDisabled);
+    }
 
     // This only supports clearing out the files, but that's OK because for
     // security reasons that's the only change the DOM is allowed to make.
     FileList* files = input->files();
     ASSERT(files);
     if (files && files->isEmpty())
         repaint();
 }
 
 static int nodeWidth(Node* node)
@@ skipping 140 matching lines @@
 }
 
 String RenderFileUploadControl::fileTextValue() const
 {
     HTMLInputElement* input = static_cast<HTMLInputElement*>(node());
     ASSERT(input->files());
     return theme()->fileListNameForWidth(input->files()->paths(), style()->font(), maxFilenameWidth());
 }
     
 } // namespace WebCore