Disable install of new default_apps for existing users

chrome/browser/extensions/external_provider_impl.cc

Index: chrome/browser/extensions/external_provider_impl.cc
diff --git a/chrome/browser/extensions/external_provider_impl.cc b/chrome/browser/extensions/external_provider_impl.cc
index 54d1cb794a966cc5a0c51459d5c9b50d3c1832ca..e27cef2707690ab99c5e5f283915c16c609f47ca 100644
--- a/chrome/browser/extensions/external_provider_impl.cc
+++ b/chrome/browser/extensions/external_provider_impl.cc
@@ -225,9 +225,15 @@ void ExternalProviderImpl::SetPrefs(DictionaryValue* prefs) {
                      << external_version << "\".";
         continue;
       }
-      service_->OnExternalExtensionFileFound(extension_id, &version, path,
-                                             crx_location_, creation_flags,
-                                             auto_acknowledge_);
+      // Don't install new default apps for existing users.
+      // TODO(grv): remove after migration (Q1-2013).
+      if ((!default_apps::isMigration) || IsOldDefaultApp(extension_id)) {

[Mihai Parparita -not on Chrome, 2012/08/27 19:31:55]

Reading global variables like this is a pretty big hack. It also spreads
knowledge of default apps across more files, instead of being localized in
default_apps.cc.

How about an alterate design where there ExternalProviderImpl subclass in
default_apps.h|cc overrides SetPrefs, and if a migration is happening, filters
out the preference keys before invoking the default SetPrefs implementation?

+        service_->OnExternalExtensionFileFound(extension_id, &version, path,
+                                               crx_location_, creation_flags,
+                                               auto_acknowledge_);
+      } else {
+        continue;
+      }
     } else { // if (has_external_update_url)
       CHECK(has_external_update_url);  // Checking of keys above ensures this.
       if (download_location_ == Extension::INVALID) {
@@ -258,6 +264,14 @@ void ExternalProviderImpl::SetPrefs(DictionaryValue* prefs) {
   service_->OnExternalProviderReady(this);
 }
 
+bool ExternalProviderImpl::IsOldDefaultApp(const std::string& extension_id) {
+  const std::string gmail_id = "pjkljhegncpnkpknbcohdijeoejaedia";
+  const std::string search_id = "coobgpohoikkiipiblmjeljniedjpjpf";
+  const std::string youtube_id = "blpcfgokakmgnkcojhhkbfbldkacnbeo";
+  return extension_id == gmail_id || extension_id == search_id
+      || extension_id == youtube_id;
+}
+
 void ExternalProviderImpl::ServiceShutdown() {
   service_ = NULL;
 }