Add JavaScript dialogs functionality to content_shell on Windows

content/shell/shell_javascript_dialog.h

Index: content/shell/shell_javascript_dialog.h
diff --git a/content/shell/shell_javascript_dialog.h b/content/shell/shell_javascript_dialog.h
index 32d425dfffe3e617e90c62dd5c9ee2c620c3abfb..a64ba39f7c6b841d5fa246867772bf447d485cad 100644
--- a/content/shell/shell_javascript_dialog.h
+++ b/content/shell/shell_javascript_dialog.h
@@ -42,7 +42,14 @@ class ShellJavaScriptDialog {
 #if defined(OS_MACOSX)
   ShellJavaScriptDialogHelper* helper_;  // owned
   NSAlert* alert_; // weak, owned by |helper_|.
-#endif  // defined(OS_MACOSX)
+#elif defined(OS_WIN)
+  ui::JavascriptMessageType message_type_;
+  HWND dialog_win_;
+  string16 message_text_;
+  string16 default_prompt_text_;
+  static INT_PTR CALLBACK DialogProc(HWND dialog, UINT message, WPARAM wparam,
+                                     LPARAM lparam);
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(ShellJavaScriptDialog);
 };