Make MockExtensionSystemFactory available in all ExtensionsTests.

extensions/browser/api_unittest.h

Index: extensions/browser/api_unittest.h
diff --git a/extensions/browser/api_unittest.h b/extensions/browser/api_unittest.h
index f26629d35e68bbdf8cd1b6d7ceb2e73ab1dd3afb..dcb09fac7a4df85b7f5b235df4e159c8ad362f5d 100644
--- a/extensions/browser/api_unittest.h
+++ b/extensions/browser/api_unittest.h
@@ -11,7 +11,6 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/testing_pref_service.h"
 #include "extensions/browser/extensions_test.h"
-#include "extensions/browser/mock_extension_system.h"
 
 namespace base {
 class Value;
@@ -92,8 +91,6 @@ class ApiUnitTest : public ExtensionsTest {
   scoped_ptr<content::TestBrowserThreadBundle> thread_bundle_;
   TestingPrefServiceSimple testing_pref_service_;
 
-  MockExtensionSystemFactory<MockExtensionSystem> extension_system_factory_;
-
   // The WebContents used to associate a RenderViewHost with API function calls,
   // or null.
   scoped_ptr<content::WebContents> contents_;