Deal gracefully with removing content settings for unregistered extensions.

chrome/browser/extensions/api/content_settings/content_settings_store.cc

 // Copyright (c) 2012 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/browser/extensions/api/content_settings/content_settings_store.h"
 
 #include <set>
 
 #include "base/debug/alias.h"
 #include "base/logging.h"
@@ skipping 217 matching lines @@
   bool notify = false;
   {
     base::AutoLock lock(lock_);
     OriginIdentifierValueMap* map = GetValueMap(ext_id, scope);
     // TODO(bauerb): This is for debugging http://crbug.com/128652.
     // Remove once the bug is fixed.
     if (!map) {
       char ext_id_buffer[33];
       base::strlcpy(ext_id_buffer, ext_id.c_str(), sizeof(ext_id_buffer));
       base::debug::Alias(ext_id_buffer);
-      // Do a clean crash.
-      CHECK(false);
+      // Gracefully return instead of crashing below.
+      return;
     }
     notify = !map->empty();
     map->clear();
   }
   if (notify) {
     NotifyOfContentSettingChanged(ext_id, scope != kExtensionPrefsScopeRegular);
   }
 }
 
 base::ListValue* ContentSettingsStore::GetSettingsForExtension(
@@ skipping 121 matching lines @@
 ContentSettingsStore::FindEntry(const std::string& ext_id) const {
   ExtensionEntryMap::const_iterator i;
   for (i = entries_.begin(); i != entries_.end(); ++i) {
     if (i->second->id == ext_id)
       return i;
   }
   return entries_.end();
 }
 
 }  // namespace extensions