Don't indent if selection is none.

Source/core/editing/ApplyBlockElementCommand.cpp

Index: Source/core/editing/ApplyBlockElementCommand.cpp
diff --git a/Source/core/editing/ApplyBlockElementCommand.cpp b/Source/core/editing/ApplyBlockElementCommand.cpp
index 5ecf67a627649d9769d1236f31b5f777fb76fb77..fe35eb03de3df545c81e1fc978509a646d16320c 100644
--- a/Source/core/editing/ApplyBlockElementCommand.cpp
+++ b/Source/core/editing/ApplyBlockElementCommand.cpp
@@ -73,8 +73,11 @@ void ApplyBlockElementCommand::doApply()
     // FIXME: We paint the gap before some paragraphs that are indented with left
     // margin/padding, but not others.  We should make the gap painting more consistent and
     // then use a left margin/padding rule here.
-    if (visibleEnd != visibleStart && isStartOfParagraph(visibleEnd))
+    if (visibleEnd != visibleStart && isStartOfParagraph(visibleEnd)) {
         setEndingSelection(VisibleSelection(visibleStart, visibleEnd.previous(CannotCrossEditingBoundary), endingSelection().isDirectional()));
+        if (endingSelection().isNone())

[Yuta Kitamura, 2014/05/20 09:44:36]

Is this logic equivalent to the following?

    VisibleSelection newSelection(visibleStart,
visibleEnd.previous(CannotCrossEditingBoundary),
endingSelection().isDirectional());
    if (newSelection().isNone())
        return;
    setEndingSelection(newSelection);

If so, I'd say my version is more readable because it exits early,
not after setEndingSelection(). Also there's slight difference in
behavior: with your version, this function ends up clearing
the ending selection which will probably affect subsequent
commands.

[yosin_UTC9, 2014/05/21 03:44:07]

Done.

Yes, you're right. Your version is better than mine.

+            return;
+    }
 
     VisibleSelection selection = selectionForParagraphIteration(endingSelection());
     VisiblePosition startOfSelection = selection.visibleStart();