Use C++11 features in core/html

Source/core/html/HTMLTableRowsCollection.cpp

Index: Source/core/html/HTMLTableRowsCollection.cpp
diff --git a/Source/core/html/HTMLTableRowsCollection.cpp b/Source/core/html/HTMLTableRowsCollection.cpp
index 6a14bddb66fad310c7a003cdeb4a52b0b4c8d510..379d744d50e3a2c773609da6aeb890750aa40576 100644
--- a/Source/core/html/HTMLTableRowsCollection.cpp
+++ b/Source/core/html/HTMLTableRowsCollection.cpp
@@ -95,7 +95,7 @@ HTMLTableRowElement* HTMLTableRowsCollection::rowAfter(HTMLTableElement& table,
         }
     }
 
-    return 0;
+    return nullptr;
 }
 
 HTMLTableRowElement* HTMLTableRowsCollection::lastRow(HTMLTableElement& table)
@@ -119,7 +119,7 @@ HTMLTableRowElement* HTMLTableRowsCollection::lastRow(HTMLTableElement& table)
             return lastRow;
     }
 
-    return 0;
+    return nullptr;
 }
 
 // Must call get() on the table in case that argument is compiled before dereferencing the