Include JNI details in the SIGQUIT output.

Also include the original command line (framework apps deliberately clobber
their argv[]).

Change-Id: I63e04cb637fa89764e8963f3d086806ae230e953
diff --git a/src/hprof/hprof.cc b/src/hprof/hprof.cc
index ccebca5..eacc73f 100644
--- a/src/hprof/hprof.cc
+++ b/src/hprof/hprof.cc
@@ -647,7 +647,7 @@
   return LookupStringId(std::string(string));
 }
 
-HprofStringId Hprof::LookupStringId(std::string string) {
+HprofStringId Hprof::LookupStringId(const std::string& string) {
   StringMapIterator it = strings_.find(string);
   if (it != strings_.end()) {
     return it->second;