REGRESSION(3.2.3 - 4.0.2): Message composing: when I undo a color change to text in Mail, undo/redo behaves strangely
<rdar://problem/7067033>
https://bugs.webkit.org/show_bug.cgi?id=30892

WebCore: 

Patch by Enrica Casucci <enrica@apple.com> on 2009-10-29
Reviewed by Darin Adler.

This problem shows in any scenario where it is necessary to split a text
node to apply a style. SplitElementCommand and WrapContentsInDummySpanCommand both
have member variables initialized in the constructor to keep reference to elements
they need to operate upon. These reference are not updated when reapplying the command.
For this reason it is necessary to guarantee that unapply doesn not delete the references
and that these commands implement doReapply to correctly reuse the existing
elements.

Test: editing/undo/redo-style.html

* editing/SplitElementCommand.cpp:
(WebCore::SplitElementCommand::executeApply): Added.
(WebCore::SplitElementCommand::doApply): Modified to call executeApply. 
(WebCore::SplitElementCommand::doUnapply): Doesn't release m_element1.
(WebCore::SplitElementCommand::doReapply): Added.
* editing/SplitElementCommand.h: Added doReapply and executeApply.
* editing/WrapContentsInDummySpanCommand.cpp:
(WebCore::WrapContentsInDummySpanCommand::executeApply): Added.
(WebCore::WrapContentsInDummySpanCommand::doApply): Modified to call executeApply.
(WebCore::WrapContentsInDummySpanCommand::doUnapply): Doesn't release m_dummySpan.
(WebCore::WrapContentsInDummySpanCommand::doReapply): Added.
* editing/WrapContentsInDummySpanCommand.h: Added doReapply and executeApply.

LayoutTests: 

Patch by Enrica Casucci <enrica@apple.com> on 2009-10-29
* editing/undo/redo-style-expected.txt: Added.
* editing/undo/redo-style.html: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@50310 268f45cc-cd09-0410-ab3c-d52691b4dbfc