Move Extension into extensions namespace

chrome/browser/ui/views/extensions/extension_view.h

Index: chrome/browser/ui/views/extensions/extension_view.h
diff --git a/chrome/browser/ui/views/extensions/extension_view.h b/chrome/browser/ui/views/extensions/extension_view.h
index 52540758e594c786ed63c5711c4ea96f23f03aea..37562f76664b2d6f15fc25dec25df76c208f00d9 100644
--- a/chrome/browser/ui/views/extensions/extension_view.h
+++ b/chrome/browser/ui/views/extensions/extension_view.h
@@ -12,10 +12,13 @@
 #include "ui/views/controls/native/native_view_host.h"
 
 class Browser;
-class Extension;
 class ExtensionHost;
 class ExtensionView;
 
+namespace extensions {
+class Extension;
+}
+
 namespace content {
 class RenderViewHost;
 }
@@ -37,7 +40,7 @@ class ExtensionView : public views::NativeViewHost {
 
   ExtensionHost* host() const { return host_; }
   Browser* browser() const { return browser_; }
-  const Extension* extension() const;
+  const extensions::Extension* extension() const;
   content::RenderViewHost* render_view_host() const;
   void DidStopLoading();
   void SetIsClipped(bool is_clipped);