Move small c/b/extensions classes into extensions namespace no.2

chrome/browser/ui/extensions/shell_window.cc

Index: chrome/browser/ui/extensions/shell_window.cc
diff --git a/chrome/browser/ui/extensions/shell_window.cc b/chrome/browser/ui/extensions/shell_window.cc
index ec323fca5e37c9c33b07fab2da1ae7a108567543..5e3f1d907cd6a54c848cb9a9cc2ccc325f52598b 100644
--- a/chrome/browser/ui/extensions/shell_window.cc
+++ b/chrome/browser/ui/extensions/shell_window.cc
@@ -72,7 +72,7 @@ ShellWindow* ShellWindow::Create(Profile* profile,
   // This object will delete itself when the window is closed.
   ShellWindow* window =
       ShellWindow::CreateImpl(profile, extension, url, params);
-  ShellWindowRegistry::Get(profile)->AddShellWindow(window);
+  extensions::ShellWindowRegistry::Get(profile)->AddShellWindow(window);
   return window;
 }
 
@@ -235,7 +235,7 @@ void ShellWindow::AddNewContents(WebContents* source,
 }
 
 void ShellWindow::OnNativeClose() {
-  ShellWindowRegistry::Get(profile_)->RemoveShellWindow(this);
+  extensions::ShellWindowRegistry::Get(profile_)->RemoveShellWindow(this);
   delete this;
 }