[debug] Extend a test and fix some typos.

test/mjsunit/debug-set-variable-value.js

Index: test/mjsunit/debug-set-variable-value.js
diff --git a/test/mjsunit/debug-set-variable-value.js b/test/mjsunit/debug-set-variable-value.js
index 65434289d002b2ce023813a6ca1e936026217407..fc4438c6f6a1c6936708b8c0f8a206112ebde46f 100644
--- a/test/mjsunit/debug-set-variable-value.js
+++ b/test/mjsunit/debug-set-variable-value.js
@@ -63,7 +63,7 @@ function RunPauseTest(scope_number, expected_old_result, variable_name,
   // Add the debug event listener.
   Debug.setListener(listener);
 
-  var actual_new_value;
+  var actual_new_result;
   try {
     actual_new_result = fun();
   } finally {
@@ -78,7 +78,7 @@ function RunPauseTest(scope_number, expected_old_result, variable_name,
   assertEquals(expected_new_result, actual_new_result);
 }
 
-// Accepts a closure 'fun' that returns a variable from it's outer scope.
+// Accepts a closure 'fun' that returns a variable from its outer scope.
 // The test changes the value of variable via the handle to function and checks
 // that the return value changed accordingly.
 function RunClosureTest(scope_number, expected_old_result, variable_name,
@@ -307,3 +307,23 @@ assertSame(Number, DebugCommandProcessor.resolveValue_(
     {handle: Debug.MakeMirror(Number).handle()}));
 assertSame(RunClosureTest, DebugCommandProcessor.resolveValue_(
     {handle: Debug.MakeMirror(RunClosureTest).handle()}));
+
+
+// Test script-scope variable.
+let abc = 12;
+{
+  function listener(event, exec_state) {
+    if (event == Debug.DebugEvent.Break) {

[jgruber, 2016/11/10 16:30:05]

FYI: Exceptions thrown in debug listeners cause a crash at a location where it
might not immediately be clear to the developer what the actual cause was (see
debug.cc:1948).

It may be better style to catch (and print) exceptions within the listener, and
check that the listener completed successfully.

But I'm also fine with landing this as-is, your call.

+      let scope_count = exec_state.frame().scopeCount();
+      let script_scope = exec_state.frame().scope(scope_count - 2);
+      assertTrue(script_scope.isScope());
+      assertEquals(debug.ScopeType.Script, script_scope.scopeType());
+      script_scope.setVariableValue('abc', 42);
+    }
+  }
+
+  Debug.setListener(listener);
+  assertEquals(12, abc);
+  debugger;
+  assertEquals(42, abc);
+}