Don't try to move non visible contents in "Indent" command

Source/core/editing/IndentOutdentCommand.cpp

Index: Source/core/editing/IndentOutdentCommand.cpp
diff --git a/Source/core/editing/IndentOutdentCommand.cpp b/Source/core/editing/IndentOutdentCommand.cpp
index d1a4480a91172acb064a3d55e1bbb72fed91d64e..a2a7a6ea5a93e0440440ffb20b3d4723af6cd9f5 100644
--- a/Source/core/editing/IndentOutdentCommand.cpp
+++ b/Source/core/editing/IndentOutdentCommand.cpp
@@ -121,7 +121,10 @@ void IndentOutdentCommand::indentIntoBlockquote(const Position& start, const Pos
         startOfContents = VisiblePosition(positionInParentAfterNode(*targetBlockquote));
     }
 
-    moveParagraphWithClones(startOfContents, VisiblePosition(end), targetBlockquote.get(), outerBlock.get());
+    VisiblePosition endOfContents = VisiblePosition(end);

[Yuta Kitamura, 2014/06/23 06:34:06]

nit: You can simplify this line with:

    VisiblePosition endOfContents(end);

[yosin_UTC9, 2014/06/23 06:52:19]

Done.

+    if (startOfContents.isNull() || endOfContents.isNull())
+        return;
+    moveParagraphWithClones(startOfContents, endOfContents, targetBlockquote.get(), outerBlock.get());
 }
 
 void IndentOutdentCommand::outdentParagraph()