Ensure settings returned from Content Settings providers are valid

components/content_settings/core/browser/content_settings_pref.cc

 // Copyright 2015 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 "components/content_settings/core/browser/content_settings_pref.h"
 
 #include <memory>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 235 matching lines @@
               kPerResourceIdentifierPrefName, &resource_dictionary)) {
         for (base::DictionaryValue::Iterator j(*resource_dictionary);
              !j.IsAtEnd();
              j.Advance()) {
           const std::string& resource_identifier(j.key());
           int setting = CONTENT_SETTING_DEFAULT;
           bool is_integer = j.value().GetAsInteger(&setting);
           DCHECK(is_integer);
           DCHECK_NE(CONTENT_SETTING_DEFAULT, setting);
           std::unique_ptr<base::Value> setting_ptr(new base::Value(setting));
+          DCHECK(IsValueAllowedForType(setting_ptr.get(), content_type_));

[msramek, 2017/05/03 20:05:42]

I'm slightly uncomfortable about this, since the user could technically edit the
Preferences file; but then again, the same is true of other preferences as well.

I can also see myself tripping on this the next time I write some migration code
and switch to another git branch.

[raymes, 2017/05/04 05:49:15]

I agree - it could just be an annoyance. But we were already doing this check
below for the non-resource identifier case and it hasn't caused any trouble yet.
I'll leave it for now and we can remove them both if it's problematic :)

           value_map_.SetValue(pattern_pair.first,
                               pattern_pair.second,
                               content_type_,
                               resource_identifier,
                               setting_ptr->DeepCopy());
         }
       }
     }
 
     const base::Value* value = nullptr;
@@ skipping 179 matching lines @@
 
 void ContentSettingsPref::AssertLockNotHeld() const {
 #if !defined(NDEBUG)
   // |Lock::Acquire()| will assert if the lock is held by this thread.
   lock_.Acquire();
   lock_.Release();
 #endif
 }
 
 }  // namespace content_settings