Fixing crash when executing ApplyStyle command.

Source/core/editing/ApplyStyleCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2008, 2009 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 794 matching lines @@
 
         Node* pastEndNode = NodeTraversal::nextSkippingChildren(*runEnd);
         if (!shouldApplyInlineStyleToRun(style, runStart, pastEndNode))
             continue;
 
         runs.append(InlineRunToApplyStyle(runStart, runEnd, pastEndNode));
     }
 
     for (size_t i = 0; i < runs.size(); i++) {
         removeConflictingInlineStyleFromRun(style, runs[i].start, runs[i].end, runs[i].pastEndNode);
-        runs[i].positionForStyleComputation = positionToComputeInlineStyleChange(runs[i].start, runs[i].dummyElement);
+        if (runs[i].startAndEndAreStillInDocument())
+            runs[i].positionForStyleComputation = positionToComputeInlineStyleChange(runs[i].start, runs[i].dummyElement);
     }
 
     document().updateLayoutIgnorePendingStylesheets();
 
-    for (size_t i = 0; i < runs.size(); i++)
-        runs[i].change = StyleChange(style, runs[i].positionForStyleComputation);
+    for (size_t i = 0; i < runs.size(); i++) {
+        if (!runs[i].positionForStyleComputation.isNull())

[yosin_UTC9, 2014/03/03 02:06:45]

nit: We can use |Position::isNotNull()| here.

[arpitab_, 2014/03/03 06:00:00]

Done.

+            runs[i].change = StyleChange(style, runs[i].positionForStyleComputation);
+    }
 
     for (size_t i = 0; i < runs.size(); i++) {
         InlineRunToApplyStyle& run = runs[i];
         if (run.dummyElement)
             removeNode(run.dummyElement);
         if (run.startAndEndAreStillInDocument())
             applyInlineStyleChange(run.start.release(), run.end.release(), run.change, AddStyledElement);
     }
 }
 
@@ skipping 707 matching lines @@
         String textToMove = nextText->data();
         insertTextIntoNode(childText, childText->length(), textToMove);
         removeNode(next);
         // don't move child node pointer. it may want to merge with more text nodes.
     }
 
     updateStartEnd(newStart, newEnd);
 }
 
 }