Make signature for 31936 more general, so as to capture more stack traces.

chrome/test/data/reliability/known_crashes.txt

 # This file contains known patterns of crash signatures. One pattern per line.
 #
 # A crash signature is the concatenation of the top N functions, delimited by
 # '___', in chrome.dll on the crash stack. All characters are lower case.
 #
 # We use crash signature patterns as our list of known crashes. A crash
 # signature pattern is a string that can be used to identify a known crash. We
 # use the notion of patterns because crashes with the same root cause can often
 # differ somewhat in their crash stacks. A pattern is intended to be a
 # generalized, yet still identifying, form of a particular crash. Usually a
@@ skipping 88 matching lines @@
 PREFIX : `anonymous namespace'::purecall____purecall___notificationservice::notify___browserlist::removebrowser___browser::~browser___browser::`scalar deleting destructor'___browserview::~browserview
 
 # 59329
 # (SUBSTRING rather than PREFIX since sometimes dies in purecall).
 SUBSTRING : pluginprocesshost::replytorenderer___pluginprocesshost::onchannelcreated___ipc::messagewithtuple<tuple1<ipc::channelhandle> >::dispatch<pluginprocesshost,void (__thiscall pluginprocesshost::*)(ipc::channelhandle const &)>
 
 # 59345
 PREFIX : windowdragresponsetask::run___messageloop::runtask
 
 # 31936
-PREFIX : webcore::uniscribehelpertextrun::uniscribehelpertextrun___webcore::font::floatwidthforcomplextext___webcore::font::floatwidth___webcore::renderimage::setimagesizeforalttext
+SUBSTRING : webcore::uniscribehelpertextrun::uniscribehelpertextrun___webcore::font::floatwidthforcomplextext
 
 # 61593
 PREFIX : webcore::font::glyphdataforcharacter___webcore::widthiterator::advance___webcore::font::floatwidthforsimpletext___webcore::font::floatwidth___webcore::renderimage::setimagesizeforalttext___webcore::renderimage::imagechanged
 
 # 61800
 PREFIX : icu_4_2::unicodestring::toutf8___normalizetext___detectlanguageofunicodetext___determinetextlanguage___renderview::capturepageinfo
 
 # 63009
 SUBSTRING : chromemain___relaunchchromebrowserwithnewcommandlineifneeded___delayedlowertoken___delayedlowertoken___relaunchchromebrowserwithnewcommandlineifneeded___delayedlowertoken___delayedlowertoken___delayedlowertoken___delayedlowertoken
 
@@ skipping 95 matching lines @@
 REGEX: std::_tree<std::_tmap_traits<std::basic_string.*,remoting::javascriptiqrequest *,std::less.*,remoting::javascriptiqrequest *> >,0> >::_lbound___std::_tree<std::_tmap_traits.*basic_string.*,extensioncontentsettingsstore::extensionentry *,std::less.*,extensioncontentsettingsstore::extensionentry *> >,0> >::find___net::sdchmanager::isinsupporteddomain___net::urlrequesthttpjob::addextraheaders
 
 # 95954
 PREFIX: net::sdchmanager::isinsupporteddomain___net::urlrequesthttpjob::addextraheaders___net::urlrequesthttpjob::start___net::urlrequest::startjob___net::urlrequest::start___urlfetcher::core::startoniothread
 
 # 96234
 PREFIX: std::_tree<std::_tmap_traits<syncable::id,int,std::less<syncable::id>,std::allocator<std::pair<syncable::id const ,int> >,0> >::_lbound___std::_tree<std::_tmap_traits<std::basic_string<char,std::char_traits<char>,std::allocator<char> >,fileapi::filesystemdirectorydatabase *,std::less<std::basic_string<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<std::pair<std::basic_string<char,std::char_traits<char>,std::allocator<char> > const ,fileapi::filesystemdirectorydatabase *> >,0> >::find___net::sdchmanager::isinsupporteddomain___net::urlrequesthttpjob::addextraheaders
 
 # 96235
 PREFIX: browser::hidebookmarkbubbleview___browserview::onwidgetmove___views::nativewidgetwin::onmove