Don't clear existing extension-defined preferences and content settings when reloading or updating…

chrome/browser/extensions/extension_prefs.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/extension_prefs.h"
 
 #include "base/prefs/pref_notifier.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ skipping 1817 matching lines @@
   }
 }
 
 void ExtensionPrefs::FinishExtensionInfoPrefs(
     const std::string& extension_id,
     const base::Time install_time,
     bool needs_sort_ordinal,
     const syncer::StringOrdinal& suggested_page_ordinal,
     DictionaryValue* extension_dict) {
   // Reinitializes various preferences with empty dictionaries.
-  extension_dict->Set(pref_names::kPrefPreferences, new DictionaryValue);
-  extension_dict->Set(pref_names::kPrefIncognitoPreferences,
-                      new DictionaryValue);
-  extension_dict->Set(pref_names::kPrefRegularOnlyPreferences,
-                      new DictionaryValue);
-  extension_dict->Set(pref_names::kPrefContentSettings, new ListValue);
-  extension_dict->Set(pref_names::kPrefIncognitoContentSettings, new ListValue);
+  if (!extension_dict->HasKey(pref_names::kPrefPreferences))

[Jeffrey Yasskin, 2013/09/06 21:31:56]

Nit: This might be clearer with a helper function:

template<typename PrefType>
static void InitializeIfNotPresent(DictionaryValue* dict, const std::string&
key) {
  if (!dict->HasKey(key))
    dict->Set(key, new PrefType);
}

[Jeffrey Yasskin, 2013/09/06 21:31:56]

I double-checked that uninstalling an extension removes the prefs (assuming I
can read code corectly), so this should be an ok change even if users are
getting around buggy extensions by uninstalling and reinstalling them.

+    extension_dict->Set(pref_names::kPrefPreferences, new DictionaryValue);
+
+  if (!extension_dict->HasKey(pref_names::kPrefIncognitoPreferences)) {
+    extension_dict->Set(pref_names::kPrefIncognitoPreferences,
+                        new DictionaryValue);
+  }
+
+  if (!extension_dict->HasKey(pref_names::kPrefRegularOnlyPreferences)) {
+    extension_dict->Set(pref_names::kPrefRegularOnlyPreferences,
+                        new DictionaryValue);
+  }
+
+  if (!extension_dict->HasKey(pref_names::kPrefContentSettings))
+    extension_dict->Set(pref_names::kPrefContentSettings, new ListValue);
+
+  if (!extension_dict->HasKey(pref_names::kPrefIncognitoContentSettings)) {
+    extension_dict->Set(pref_names::kPrefIncognitoContentSettings,
+                        new ListValue);
+  }
 
   // If this point has been reached, any pending installs should be considered
   // out of date.
   extension_dict->Remove(kDelayedInstallInfo, NULL);
 
   // Clear state that may be registered from a previous install.
   extension_dict->Remove(EventRouter::kRegisteredEvents, NULL);
 
   // FYI, all code below here races on sudden shutdown because
   // |extension_dict|, |extension_sorting_|, |extension_pref_value_map_|,
@@ skipping 11 matching lines @@
     is_enabled = initial_state == Extension::ENABLED;
   }
 
   extension_pref_value_map_->RegisterExtension(extension_id, install_time,
                                                is_enabled);
   content_settings_store_->RegisterExtension(extension_id, install_time,
                                              is_enabled);
 }
 
 }  // namespace extensions