Add null check to fix crash in blink::ComputedStyle::display

third_party/WebKit/Source/core/editing/EditingUtilities.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 747 matching lines @@
     return nextPositionOfAlgorithm<EditingInFlatTreeStrategy>(position, moveType);
 }
 
 bool isEnclosingBlock(const Node* node)
 {
     return node && node->layoutObject() && !node->layoutObject()->isInline() && !node->layoutObject()->isRubyText();
 }
 
 bool isInline(const Node* node)
 {
-    return node && node->computedStyle()->display() == INLINE;
+    return node && node->computedStyle() && node->computedStyle()->display() == INLINE;

[yosin_UTC9, 2016/07/14 01:08:52]

Since |Node::computedStyle()| isn't simple getter,
could you use local variable to hold |ComputedStyle| to avoid calling
|Node::computedStyle()| twice?

[joone, 2016/07/14 07:06:54]

Done.

 }
 
 // TODO(yosin) Deploy this in all of the places where |enclosingBlockFlow()| and
 // |enclosingBlockFlowOrTableElement()| are used.
 // TODO(yosin) Callers of |Node| version of |enclosingBlock()| should use
 // |Position| version The enclosing block of [table, x] for example, should be
 // the block that contains the table and not the table, and this function should
 // be the only one responsible for knowing about these kinds of special cases.
 Element* enclosingBlock(Node* node, EditingBoundaryCrossingRule rule)
 {
@@ skipping 1033 matching lines @@
 {
     if (!RuntimeEnabledFeatures::inputEventEnabled())
         return DispatchEventResult::NotCanceled;
     if (!target)
         return DispatchEventResult::NotCanceled;
     InputEvent* beforeInputEvent = InputEvent::createBeforeInput(inputType, data, InputEvent::EventCancelable::IsCancelable, InputEvent::EventIsComposing::NotComposing, ranges);
     return target->dispatchEvent(beforeInputEvent);
 }
 
 } // namespace blink