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

chrome/browser/background/background_contents_service_unittest.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 <string>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/utf_string_conversions.h"
@@ skipping 22 matching lines @@
 
   const DictionaryValue* GetPrefs(Profile* profile) {
     return profile->GetPrefs()->GetDictionary(
         prefs::kRegisteredBackgroundContents);
   }
 
   // Returns the stored pref URL for the passed app id.
   std::string GetPrefURLForApp(Profile* profile, const string16& appid) {
     const DictionaryValue* pref = GetPrefs(profile);
     EXPECT_TRUE(pref->HasKey(UTF16ToUTF8(appid)));
-    DictionaryValue* value;
+    const DictionaryValue* value;
     pref->GetDictionaryWithoutPathExpansion(UTF16ToUTF8(appid), &value);
     std::string url;
     value->GetString("url", &url);
     return url;
   }
 
   scoped_ptr<CommandLine> command_line_;
 };
 
 class MockBackgroundContents : public BackgroundContents {
@@ skipping 172 matching lines @@
   contents->Navigate(url);
   EXPECT_EQ(1U, GetPrefs(&profile)->size());
   contents2->Navigate(url2);
   EXPECT_EQ(2U, GetPrefs(&profile)->size());
   service.ShutdownAssociatedBackgroundContents(ASCIIToUTF16("appid"));
   EXPECT_FALSE(service.IsTracked(contents));
   EXPECT_EQ(NULL, service.GetAppBackgroundContents(ASCIIToUTF16("appid")));
   EXPECT_EQ(1U, GetPrefs(&profile)->size());
   EXPECT_EQ(url2.spec(), GetPrefURLForApp(&profile, contents2->appid()));
 }