[chromedriver] Support clicking an element in sub frames.

chrome/test/chromedriver/session_commands.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/test/chromedriver/session_commands.h"
 
 #include <list>
 
 #include "base/callback.h"
 #include "base/logging.h"  // For CHECK macros.
@@ skipping 140 matching lines @@
       if (window_name == name) {
         web_view = *it;
         break;
       }
     }
   }
 
   if (!web_view)
     return Status(kNoSuchWindow);
   session->window = web_view->GetId();
-  session->frame = "";
+  session->SwitchToTopFrame();
   session->mouse_position = WebPoint(0, 0);
   return Status(kOk);
 }
 
 Status ExecuteSetTimeout(
     Session* session,
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value) {
   int ms;
   if (!params.GetInteger("ms", &ms) || ms < 0)
@@ skipping 67 matching lines @@
 
 Status ExecuteDismissAlert(
     Session* session,
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value) {
   Status status = session->chrome->HandleJavaScriptDialog(
       false, session->prompt_text);
   session->prompt_text = "";
   return status;
 }