Implement lock contention event logging.

Change-Id: I88b30985590157bb5d04229a97f191b898f141bb
diff --git a/src/runtime.h b/src/runtime.h
index 1ca9dca..cbd47b8 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -56,6 +56,8 @@
     size_t heap_initial_size_;
     size_t heap_maximum_size_;
     size_t stack_size_;
+    uint32_t lock_profiling_threshold_;
+    bool (*hook_is_sensitive_thread_)();
     jint (*hook_vfprintf_)(FILE* stream, const char* format, va_list ap);
     void (*hook_exit_)(jint status);
     void (*hook_abort_)();