Do not crash if custom scrollbars have -webkit-appearane:searchfield-foo.

Source/core/rendering/RenderThemeChromiumSkia.cpp

 /*
  * Copyright (C) 2007 Apple Inc.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Collabora Ltd.
  * Copyright (C) 2008, 2009 Google Inc.
  *
  * 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.
@@ skipping 204 matching lines @@
     partRect.move(offsetFromInputRenderer);
     // Account for the local drawing offset.
     partRect.move(localOffset.x(), localOffset.y());
 
     return pixelSnappedIntRect(partRect);
 }
 
 bool RenderThemeChromiumSkia::paintSearchFieldCancelButton(RenderObject* cancelButtonObject, const PaintInfo& paintInfo, const IntRect& r)
 {
     // Get the renderer of <input> element.
+    if (!cancelButtonObject->node())
+        return false;
     Node* input = cancelButtonObject->node()->shadowHost();
     RenderObject* baseRenderer = input ? input->renderer() : cancelButtonObject;
     if (!baseRenderer->isBox())
         return false;
     RenderBox* inputRenderBox = toRenderBox(baseRenderer);
     LayoutRect inputContentBox = inputRenderBox->contentBoxRect();
 
     // Make sure the scaled button stays square and will fit in its parent's box.
     LayoutUnit cancelButtonSize = std::min(inputContentBox.width(), std::min<LayoutUnit>(inputContentBox.height(), r.height()));
     // Calculate cancel button's coordinates relative to the input element.
@@ skipping 23 matching lines @@
     float fontScale = style->fontSize() / defaultControlFontPixelSize;
     int magnifierSize = lroundf(std::min(std::max(minSearchFieldResultsDecorationSize, defaultSearchFieldResultsDecorationSize * fontScale),
                                          maxSearchFieldResultsDecorationSize));
     style->setWidth(Length(magnifierSize, Fixed));
     style->setHeight(Length(magnifierSize, Fixed));
 }
 
 bool RenderThemeChromiumSkia::paintSearchFieldResultsDecoration(RenderObject* magnifierObject, const PaintInfo& paintInfo, const IntRect& r)
 {
     // Get the renderer of <input> element.
+    if (!magnifierObject->node())
+        return false;
     Node* input = magnifierObject->node()->shadowHost();
     RenderObject* baseRenderer = input ? input->renderer() : magnifierObject;
     if (!baseRenderer->isBox())
         return false;
     RenderBox* inputRenderBox = toRenderBox(baseRenderer);
     LayoutRect inputContentBox = inputRenderBox->contentBoxRect();
 
     // Make sure the scaled decoration stays square and will fit in its parent's box.
     LayoutUnit magnifierSize = std::min(inputContentBox.width(), std::min<LayoutUnit>(inputContentBox.height(), r.height()));
     // Calculate decoration's coordinates relative to the input element.
@@ skipping 194 matching lines @@
 }
 
 RenderThemeChromiumSkia::DirectionFlippingScope::~DirectionFlippingScope()
 {
     if (!m_needsFlipping)
         return;
     m_paintInfo.context->restore();
 }
 
 } // namespace WebCore