Enable extensions by default.

BUG=20573
TEST=Install sample extensions without modifying command line flags. They should install (and run on next startup).

Review URL: http://codereview.chromium.org/179032

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@24846 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extensions_service.cc b/chrome/browser/extensions/extensions_service.cc
index b53f243..7b1c230 100644
--- a/chrome/browser/extensions/extensions_service.cc
+++ b/chrome/browser/extensions/extensions_service.cc
@@ -95,14 +95,14 @@
       extension_prefs_(new ExtensionPrefs(prefs, install_directory)),
       backend_loop_(backend_loop),
       install_directory_(install_directory),
-      extensions_enabled_(false),
+      extensions_enabled_(true),
       show_extensions_prompts_(true),
       ready_(false) {
   // Figure out if extension installation should be enabled.
-  if (command_line->HasSwitch(switches::kEnableExtensions)) {
-    extensions_enabled_ = true;
-  } else if (profile->GetPrefs()->GetBoolean(prefs::kEnableExtensions)) {
-    extensions_enabled_ = true;
+  if (command_line->HasSwitch(switches::kDisableExtensions)) {
+    extensions_enabled_ = false;
+  } else if (profile->GetPrefs()->GetBoolean(prefs::kDisableExtensions)) {
+    extensions_enabled_ = false;
   }
 
   // Set up the ExtensionUpdater