Ensure we never remove the style attribute when syncing it from CSSOM.

third_party/WebKit/LayoutTests/editing/undo/remove-css-property-and-remove-style-expected.txt

-This tests removing style attribute after removing CSS property. Undo should bring back the CSS property we removed.
+This tests removing style after removing CSS property. Undo should bring back the CSS property we removed.
 
 Initially "test" should be bold wrapped with a span:
 | <span>
 |   style="font-weight: 900;"
 |   "test"
 
 Unbolding should remove the CSS style and also remove the span:
 | "<#selection-anchor>test<#selection-focus>"
 
-Undo should bring back both the span and style attribute so that "test" is once again bold:
+Undo should bring back both the span and style so that "test" is once again bold:
 | <span>
 |   style="font-weight: 900;"
 |   "<#selection-anchor>test<#selection-focus>"
 
 Redo should unbold "test" and there should be no span:
 | "<#selection-anchor>test<#selection-focus>"
 
 Undo once more:
 | <span>
 |   style="font-weight: 900;"
 |   "<#selection-anchor>test<#selection-focus>"
 
 Reset, and added id and title:
 | <span>
 |   id="test_span"
 |   style="font-weight: 900;"
 |   title="hello, world"
 |   "test"
 
 Unbolding should remove the CSS style but shouldn't remove the span:
 | <span>
 |   id="test_span"
+|   style=""
 |   title="hello, world"
 |   "<#selection-anchor>test<#selection-focus>"
 
-Undo should restore the style attribute and "test" should be bold:
+Undo should restore the style and "test" should be bold:
 | <span>
 |   id="test_span"
 |   style="font-weight: 900;"
 |   title="hello, world"
 |   "<#selection-anchor>test<#selection-focus>"
 
-Redo should remove the style attribute again:
+Redo should remove the style again:
 | <span>
 |   id="test_span"
+|   style=""
 |   title="hello, world"
 |   "<#selection-anchor>test<#selection-focus>"
 
 Reset, and added color:blue:
 | <span>
 |   style="font-weight: 900; color: blue;"
 |   "test"
 
-Unbolding should remove the font-weight but shouldn't remove the style attribute:
+Unbolding should remove the font-weight but shouldn't remove the style :
 | <span>
 |   style="color: blue;"
 |   "<#selection-anchor>test<#selection-focus>"
 
-Undo should reset the style attribute so that "test" is both bold and blue:
+Undo should reset the style so that "test" is both bold and blue:
 | <span>
 |   style="color: blue; font-weight: 900;"
 |   "<#selection-anchor>test<#selection-focus>"
 
 Redo should only remove font-weight and leave "test" blue:
 | <span>
 |   style="color: blue;"
 |   "<#selection-anchor>test<#selection-focus>"
 
-Setting the forecolor to black should remove both the style attribute and the span:
+Setting the forecolor to black should remove both the style and the span:
 | "<#selection-anchor>test<#selection-focus>"
 
 Undo should make "test" blue again:
 | <span>
 |   style="color: blue;"
 |   "<#selection-anchor>test<#selection-focus>"