Fixing crash when executing ApplyStyle command.

Source/core/editing/ApplyStyleCommand.cpp

Index: Source/core/editing/ApplyStyleCommand.cpp
diff --git a/Source/core/editing/ApplyStyleCommand.cpp b/Source/core/editing/ApplyStyleCommand.cpp
index 966eea4a23de22c26d4cc6a017be3c59dd033627..0455946c8e633e6da310715907b14aad0213361a 100644
--- a/Source/core/editing/ApplyStyleCommand.cpp
+++ b/Source/core/editing/ApplyStyleCommand.cpp
@@ -812,13 +812,16 @@ void ApplyStyleCommand::applyInlineStyleToNodeRange(EditingStyle* style, PassRef
 
     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];