StackTraceElements really want PrettyDescriptor, not PrettyClass.

Change-Id: I69dc735da0148c0c40805e6cd0c5662ced40f607
diff --git a/src/thread.cc b/src/thread.cc
index b11dbbd..49c9605 100644
--- a/src/thread.cc
+++ b/src/thread.cc
@@ -1115,11 +1115,11 @@
     uint32_t native_pc = pc_trace->Get(i);
     Class* klass = method->GetDeclaringClass();
     const DexFile& dex_file = class_linker->FindDexFile(klass->GetDexCache());
-    String* readable_descriptor = String::AllocFromModifiedUtf8(PrettyClass(klass).c_str());
+    std::string class_name(PrettyDescriptor(klass->GetDescriptor()));
 
     // Allocate element, potentially triggering GC
     StackTraceElement* obj =
-        StackTraceElement::Alloc(readable_descriptor,
+        StackTraceElement::Alloc(String::AllocFromModifiedUtf8(class_name.c_str()),
                                  method->GetName(),
                                  klass->GetSourceFile(),
                                  dex_file.GetLineNumFromPC(method,