Description of problem:
Drag-selecting any page crashes Mac builds in NSGetFactory


Version-Release number of selected component (if applicable):

How reproducible:


Steps to Reproduce:
1) View any web page. (I used the default sample page,
resource:/res/samples/test0.html)

2) Drag-select the page. (Specifically, while holding down 
the mouse button, drag the mouse pointer downwards from any 
point in the browser's content region to the bottom of the 
browser's content region.)                   

  
Actual results:
The application crashed. Stack crawl appended below from MacsBug.


Expected results:
The window should scroll downwards. Scrolled content should be selected. 
(Or, at least, the application should not crash.)


Additional info:
Win32: if you receive a Dr. Watson error, please note the type of the crash, 
and the module that the application crashed in. (e.g. access violation in 
apprunner.exe) 
Mac OS: if you're running MacsBug, please provide the results of a how and an 
sc: 
*** MACSBUG STACK CRAWL OF CRASH (Mac OS)
Calling chain using A6/R1 links 
Back chain  ISA  Caller 
00000000    PPC  0BA85E74   
03AEFD80    PPC  0B742248   
03AEFD30    PPC  0B50FDDC  NSGetFactory+027FC
PowerPC unmapped memory exception at 0B512BD0 NSGetFactory+055F0