Added code to allow method tracing from command line.

Crated a set of command line switches to allow method tracing to be
enabled from the command line. They are -Xmethod-trace,
-Xmethod-trace-file, and -Xmethod-trace-file-size.

Change-Id: I7ecaa07aba3d7ca41f2ff3a9a9341d97833afe36
diff --git a/src/runtime.h b/src/runtime.h
index a2ec08e..4bbe54e 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -77,6 +77,9 @@
     size_t jni_globals_max_;
     size_t lock_profiling_threshold_;
     std::string stack_trace_file_;
+    bool method_trace_;
+    std::string method_trace_file_;
+    size_t method_trace_file_size_;
     bool (*hook_is_sensitive_thread_)();
     jint (*hook_vfprintf_)(FILE* stream, const char* format, va_list ap);
     void (*hook_exit_)(jint status);
@@ -321,6 +324,9 @@
   bool stats_enabled_;
   RuntimeStats stats_;
 
+  bool method_trace_;
+  std::string method_trace_file_;
+  size_t method_trace_file_size_;
   Trace* tracer_;
 
   typedef std::map<const ClassLoader*, std::vector<const DexFile*> > CompileTimeClassPaths;