Fix scoping of v8::HandleScope to prevent use-after-dispose

R=jkummerow@chromium.org
TEST=shell_g doesn't crash

Review URL: https://chromiumcodereview.appspot.com/9959014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11195 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

samples/shell.cc

-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -67,17 +67,20 @@ static bool run_shell;
 int main(int argc, char* argv[]) {
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
   run_shell = (argc == 1);
-  v8::HandleScope handle_scope;
-  v8::Persistent<v8::Context> context = CreateShellContext();
-  if (context.IsEmpty()) {
-    printf("Error creating context\n");
-    return 1;
+  int result;
+  {
+    v8::HandleScope handle_scope;
+    v8::Persistent<v8::Context> context = CreateShellContext();
+    if (context.IsEmpty()) {
+      printf("Error creating context\n");
+      return 1;
+    }
+    context->Enter();
+    result = RunMain(argc, argv);
+    if (run_shell) RunShell(context);
+    context->Exit();
+    context.Dispose();
   }
-  context->Enter();
-  int result = RunMain(argc, argv);
-  if (run_shell) RunShell(context);
-  context->Exit();
-  context.Dispose();
   v8::V8::Dispose();
   return result;
 }