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

chrome/browser/extensions/extension_prefs.cc

Index: chrome/browser/extensions/extension_prefs.cc
diff --git a/chrome/browser/extensions/extension_prefs.cc b/chrome/browser/extensions/extension_prefs.cc
index 24f2d84a2650d97d2d3f478826576e478b30d183..3c66561322b308e369e426e79ba805e4f3440c34 100644
--- a/chrome/browser/extensions/extension_prefs.cc
+++ b/chrome/browser/extensions/extension_prefs.cc
@@ -1835,13 +1835,26 @@ void ExtensionPrefs::FinishExtensionInfoPrefs(
     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.