Move Extension into extensions namespace

chrome/browser/extensions/extension_apitest.h

Index: chrome/browser/extensions/extension_apitest.h
diff --git a/chrome/browser/extensions/extension_apitest.h b/chrome/browser/extensions/extension_apitest.h
index 28ec8b45a5226d8fb1dfcb2bae20bf61ad070724..9e34373fa894d55d74e8a253988cf4576ea3dc6d 100644
--- a/chrome/browser/extensions/extension_apitest.h
+++ b/chrome/browser/extensions/extension_apitest.h
@@ -14,13 +14,16 @@
 #include "chrome/browser/extensions/extension_browsertest.h"
 #include "content/public/browser/notification_registrar.h"
 
+class FilePath;
+
+namespace extensions {
+class Extension;
+}
+
 namespace ui_test_utils {
 class TestWebSocketServer;
 }
 
-class Extension;
-class FilePath;
-
 // The general flow of these API tests should work like this:
 // (1) Setup initial browser state (e.g. create some bookmarks for the
 //     bookmark test)
@@ -148,7 +151,7 @@ class ExtensionApiTest : public ExtensionBrowserTest {
 
   // Test that exactly one extension loaded.  If so, return a pointer to
   // the extension.  If not, return NULL and set message_.
-  const Extension* GetSingleLoadedExtension();
+  const extensions::Extension* GetSingleLoadedExtension();
 
   // All extensions tested by ExtensionApiTest are in the "api_test" dir.
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE;