[Bug 30653] New: Deleting text from richedit controls extremely slow

http://bugs.winehq.org/show_bug.cgi?id=30653

Bug #: 30653
           Summary: Deleting text from richedit controls extremely slow
           Product: Wine
           Version: 1.5.4
          Platform: x86
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: richedit
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
    Classification: Unclassified

The attached program creates a richedit control containing $1 
lines of text, then times how long it takes to delete the first 1000 lines.  
Results on my e7300 from running "wine delete.exe 5000":
  Builtin riched20: 97500 ms
  Native riched20: 1800 ms
i.e. builtin is about 50 times slower than native.   
It gets worse fast as you add lines.

+relay shows InvalidateRect is called a bazillion times (like in bug 30614).

The attached patch optimizes ME_InvalidateMarkedParagraphs to only
call InvalidateRect once per run of invalid paragraphs, and makes
deletion merely slow instead of crazy slow.