Alex Miller reported that when very long strings were constructed
and inserted into an HTML document, the browser would incorrectly 
construct the layout objects used to display the text. 
Under such conditions an incorrect length would be calculated for 
a text run resulting in too small of a memory buffer being allocated 
to store the text. 
This issue could be used by an attacker to write data past the end 
of the buffer and execute malicious code on a victim's computer.