[Interpreter] Adds support to fetch return value on break at return.

src/debug/debug.h

Index: src/debug/debug.h
diff --git a/src/debug/debug.h b/src/debug/debug.h
index 600bc1a605bd6349f20faa983b473050ab5a3d9e..3e59adea1d0637c7e6a464cbc8be892a097ac0a4 100644
--- a/src/debug/debug.h
+++ b/src/debug/debug.h
@@ -427,8 +427,8 @@ class Debug {
 
   // Internal logic
   bool Load();
-  void Break(Arguments args, JavaScriptFrame*);
-  Object* SetAfterBreakTarget(JavaScriptFrame* frame);
+  void Break(JavaScriptFrame* frame);
+  void SetAfterBreakTarget(JavaScriptFrame* frame);
 
   // Scripts handling.
   Handle<FixedArray> GetLoadedScripts();
@@ -524,6 +524,11 @@ class Debug {
   StackFrame::Id break_frame_id() { return thread_local_.break_frame_id_; }
   int break_id() { return thread_local_.break_id_; }
 
+  Handle<Object> return_value() { return thread_local_.return_value_; }
+  void set_return_value(Handle<Object> value) {
+    thread_local_.return_value_ = value;
+  }
+
   // Support for embedding into generated code.
   Address is_active_address() {
     return reinterpret_cast<Address>(&is_active_);
@@ -678,6 +683,10 @@ class Debug {
     // Stores the way how LiveEdit has patched the stack. It is used when
     // debugger returns control back to user script.
     LiveEdit::FrameDropMode frame_drop_mode_;
+
+    // Value of accumulator in interpreter frames. In non-interpreter frames
+    // this value will be the hole.
+    Handle<Object> return_value_;
   };
 
   // Storage location for registers when handling debug break calls
@@ -719,6 +728,7 @@ class DebugScope BASE_EMBEDDED {
   DebugScope* prev_;               // Previous scope if entered recursively.
   StackFrame::Id break_frame_id_;  // Previous break frame id.
   int break_id_;                   // Previous break id.
+  Handle<Object> return_value_;    // Previous result.
   bool failed_;                    // Did the debug context fail to load?
   SaveContext save_;               // Saves previous context.
   PostponeInterruptsScope no_termination_exceptons_;