Include the map name when dumping memory around a register.

Bug: http://b/19590178
Test: ran tests, ran crasher
Change-Id: Ib9afa34c860d8732ef1943eb4decd0b7c8fb55fd
diff --git a/libbacktrace/BacktraceMap.cpp b/libbacktrace/BacktraceMap.cpp
index c8a500c..bdae140 100644
--- a/libbacktrace/BacktraceMap.cpp
+++ b/libbacktrace/BacktraceMap.cpp
@@ -24,11 +24,21 @@
 
 #include <log/log.h>
 
-#include <backtrace/backtrace_constants.h>
+#include <android-base/stringprintf.h>
+#include <backtrace/Backtrace.h>
 #include <backtrace/BacktraceMap.h>
+#include <backtrace/backtrace_constants.h>
 
 #include "thread_utils.h"
 
+using android::base::StringPrintf;
+
+std::string backtrace_map_t::Name() const {
+  if (!name.empty()) return name;
+  if (start == 0 && end == 0) return "";
+  return StringPrintf("<anonymous:%" PRIPTR ">", start);
+}
+
 BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
   if (pid_ < 0) {
     pid_ = getpid();