Add support for JavaScript alert, confirm, prompt and onbeforeunload dialogs (issue #507).

- Add CefJSDialogHandler and CefJSDialogCallback interfaces.
- Add default dialog implementations for Windows and Mac OS-X.
- Add "JavaScript Dialogs" example to cefclient.
- Change TestHandler::AddResource to ignore the query component when matching URLs.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@594 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

include/cef_client.h

@@ -41,6 +41,7 @@
 #include "include/cef_base.h"
 #include "include/cef_display_handler.h"
 #include "include/cef_geolocation_handler.h"
+#include "include/cef_jsdialog_handler.h"
 #include "include/cef_life_span_handler.h"
 #include "include/cef_load_handler.h"
 #include "include/cef_process_message.h"
@@ -93,6 +94,15 @@ class CefClient : public virtual CefBase {
     return NULL;
   }
 
+  ///
+  // Return the handler for JavaScript dialogs. If no handler is provided the
+  // default implementation will be used.
+  ///
+  /*--cef()--*/
+  virtual CefRefPtr<CefJSDialogHandler> GetJSDialogHandler() {
+    return NULL;
+  }
+
   ///
   // Called when a new message is received from a different process. Return true
   // if the message was handled or false otherwise. Do not keep a reference to