Fix the crash of issue 2209773002

third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 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.
@@ skipping 366 matching lines @@
         return NoMove;
     }
     if ((point1.x() - point2.x()).abs() >= (point1.y() - point2.y()).abs()) {
         return Horizontal;
     }
     return Vertical;
 }
 
 bool SliderContainerElement::canSlide()
 {
-    DCHECK(hostInput()->layoutObject());
-    const ComputedStyle& sliderStyle = hostInput()->layoutObject()->styleRef();
-    const TransformOperations& transforms = sliderStyle.transform();
+    if (!hostInput() || !hostInput()->layoutObject() || !hostInput()->layoutObject()->style()) {
+        return false;
+    }
+    const ComputedStyle* sliderStyle = hostInput()->layoutObject()->style();
+    const TransformOperations& transforms = sliderStyle->transform();
     int transformSize = transforms.size();
     if (transformSize > 0) {
         for (int i = 0; i < transformSize; ++i) {
             if (transforms.at(i)->type() == TransformOperation::Rotate) {
                 return true;
             }
         }
     }
-    if ((m_slidingDirection == Vertical && sliderStyle.appearance() == SliderHorizontalPart) || (m_slidingDirection == Horizontal && sliderStyle.appearance() == SliderVerticalPart)) {
+    if ((m_slidingDirection == Vertical && sliderStyle->appearance() == SliderHorizontalPart) || (m_slidingDirection == Horizontal && sliderStyle->appearance() == SliderVerticalPart)) {
         return false;
     }
     return true;
 }
 
 const AtomicString& SliderContainerElement::shadowPseudoId() const
 {
     DEFINE_STATIC_LOCAL(const AtomicString, mediaSliderContainer, ("-webkit-media-slider-container"));
     DEFINE_STATIC_LOCAL(const AtomicString, sliderContainer, ("-webkit-slider-container"));
 
@@ skipping 32 matching lines @@
     HTMLElement::didMoveToNewDocument(oldDocument);
 }
 
 void SliderContainerElement::removeAllEventListeners()
 {
     Node::removeAllEventListeners();
     m_hasTouchEventHandler = false;
 }
 
 } // namespace blink