[wasm] Stack inspection support for asm.js frames

src/frames.h

Index: src/frames.h
diff --git a/src/frames.h b/src/frames.h
index 373f4de92c63309290940ae06f6ff48f87fc706b..b363b90dc29f02d4a6335509818fab0c0d86547d 100644
--- a/src/frames.h
+++ b/src/frames.h
@@ -734,6 +734,7 @@ class StandardFrame : public StackFrame {
   virtual Object* receiver() const;
   virtual Script* script() const;
   virtual Object* context() const;
+  virtual int position() const;
 
   // Access the expressions in the stack frame including locals.
   inline Object* GetExpression(int index) const;
@@ -957,6 +958,9 @@ class InterpretedFrame : public JavaScriptFrame {
  public:
   Type type() const override { return INTERPRETED; }
 
+  // Accessors.
+  int position() const override;
+
   // Lookup exception handler for current {pc}, returns -1 if none found.
   int LookupExceptionHandlerInTable(
       int* data, HandlerTable::CatchPrediction* prediction) override;
@@ -1067,6 +1071,7 @@ class WasmFrame : public StandardFrame {
   Object* wasm_obj() const;
   uint32_t function_index() const;
   Script* script() const override;
+  int position() const override;
 
   static WasmFrame* cast(StackFrame* frame) {
     DCHECK(frame->is_wasm());