Stub to capture method entry/exit.

Added stubs to allow traceview to do method tracing. Currently only
outputs to logcat, and a later change will generate the proper log file.

Change-Id: Icaafc50e2eaf042ddc4d882011f7e8121bdd8b1c
diff --git a/src/stack.h b/src/stack.h
index eee1d56..868b157 100644
--- a/src/stack.h
+++ b/src/stack.h
@@ -53,6 +53,8 @@
 
   uintptr_t GetReturnPC() const;
 
+  void SetReturnPC(uintptr_t pc);
+
   uintptr_t LoadCalleeSave(int num) const;