ChromeDriver should be able to focus on a frame using its frame element,

chrome/test/webdriver/session.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_TEST_WEBDRIVER_SESSION_H_
 #define CHROME_TEST_WEBDRIVER_SESSION_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 100 matching lines @@
   // |GetWindowIds| or the name attribute of a DOM window.
   ErrorCode SwitchToWindow(const std::string& name);
 
   // Switches the frame used by default. |name_or_id| is either the name or id
   // of a frame element.
   ErrorCode SwitchToFrameWithNameOrId(const std::string& name_or_id);
 
   // Switches the frame used by default. |index| is the zero-based frame index.
   ErrorCode SwitchToFrameWithIndex(int index);
 
+  // Switches to the frame identified by the given |element|. The element must
+  // be either an IFRAME or FRAME element.
+  ErrorCode SwitchToFrameWithElement(const WebElementId& element);
+
   // Switches the frame used by default to the topmost frame.
   void SwitchToTopFrame();
 
   // Closes the current window. Returns true on success.
   // Note: The session will be deleted if this closes the last window in the
   // session.
   bool CloseWindow();
 
   // Gets the version of the running browser.
   std::string GetVersion();
@@ skipping 90 matching lines @@
   FrameId current_target_;
 
   DISALLOW_COPY_AND_ASSIGN(Session);
 };
 
 }  // namespace webdriver
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(webdriver::Session);
 
 #endif  // CHROME_TEST_WEBDRIVER_SESSION_H_