Move Extension into extensions namespace

chrome/browser/renderer_host/chrome_render_view_host_observer.h

Index: chrome/browser/renderer_host/chrome_render_view_host_observer.h
diff --git a/chrome/browser/renderer_host/chrome_render_view_host_observer.h b/chrome/browser/renderer_host/chrome_render_view_host_observer.h
index 3d43e53d1ba3051e5afd2e9aa81b3ed1720d4599..0092ba115a26cfee1553cfe1c2f84fb2126f2201 100644
--- a/chrome/browser/renderer_host/chrome_render_view_host_observer.h
+++ b/chrome/browser/renderer_host/chrome_render_view_host_observer.h
@@ -8,12 +8,15 @@
 
 #include "content/public/browser/render_view_host_observer.h"
 
+class Profile;
+
 namespace chrome_browser_net {
 class Predictor;
 }
 
+namespace extensions {
 class Extension;
-class Profile;
+}
 
 // This class holds the Chrome specific parts of RenderViewHost, and has the
 // same lifetime.
@@ -37,7 +40,7 @@ class ChromeRenderViewHostObserver : public content::RenderViewHostObserver {
    // created by a RenderViewHost.
   void InitRenderViewForExtensions();
   // Gets the extension or app (if any) that is associated with the RVH.
-  const Extension* GetExtension();
+  const extensions::Extension* GetExtension();
   // Cleans up when a RenderViewHost is removed, or on destruction.
   void RemoveRenderViewHostForExtensions(content::RenderViewHost* rvh);
   void OnFocusedEditableNodeTouched();