[7u] Review request for 8015375: Edits to text components hang for clipboard access

[dmitry markov]

Hello,

Please review the back-port of the fix for 8015375 to jdk7u. The changes 
are the same.

bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8015375
webrev for jdk7u-dev: http://cr.openjdk.java.net/~dmarkov/8015375/webrev.00/
jdk8 changeset: http://hg.openjdk.java.net/jdk8/awt/jdk/rev/8b274eccd94a
technical review for jdk8: 
http://mail.openjdk.java.net/pipermail/awt-dev/2013-June/004924.html

Thanks,
Dmitry