Correct const accessors in base/values.(h|cc)

chrome/test/webdriver/commands/target_locator_commands.cc

 // 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.
 
 #include "chrome/test/webdriver/commands/target_locator_commands.h"
 
 #include "base/string_number_conversions.h"
 #include "base/values.h"
 #include "chrome/test/webdriver/commands/response.h"
 #include "chrome/test/webdriver/webdriver_element_id.h"
@@ skipping 115 matching lines @@
     session_->SwitchToTopFrame();
   } else {
     error = new Error(kBadRequest, "Invalid 'id' parameter");
   }
   if (error)
     response->SetError(error);
 }
 
 bool SwitchFrameCommand::GetWebElementParameter(const std::string& key,
                                                 ElementId* out) const {
-  DictionaryValue* value;
+  const DictionaryValue* value;
   if (!GetDictionaryParameter(key, &value))
     return false;
 
   ElementId id(value);
   if (!id.is_valid())
     return false;
 
   *out = id;
   return true;
 }
@@ skipping 15 matching lines @@
   Error* error = session_->ExecuteScript(
       "return document.activeElement || document.body", &args, &result);
   if (error) {
     response->SetError(error);
     return;
   }
   response->SetValue(result);
 }
 
 }  // namespace webdriver