Move Extension into extensions namespace

chrome/browser/extensions/extension_tab_util.h

Index: chrome/browser/extensions/extension_tab_util.h
diff --git a/chrome/browser/extensions/extension_tab_util.h b/chrome/browser/extensions/extension_tab_util.h
index ed0f1a51900cfb5dd6c3ea3165691b75ed9cc062..d6659e6599879a021085b8ff1267add73a86c551 100644
--- a/chrome/browser/extensions/extension_tab_util.h
+++ b/chrome/browser/extensions/extension_tab_util.h
@@ -9,7 +9,6 @@
 #include <string>
 
 class Browser;
-class Extension;
 class GURL;
 class Profile;
 class TabContentsWrapper;
@@ -24,6 +23,10 @@ namespace content {
 class WebContents;
 }
 
+namespace extensions {
+class Extension;
+}
+
 // Provides various utility functions that help manipulate tabs.
 class ExtensionTabUtil {
  public:
@@ -71,7 +74,7 @@ class ExtensionTabUtil {
   // extension base, we decided it wasn't worth breaking existing extensions to
   // fix.
   static GURL ResolvePossiblyRelativeURL(const std::string& url_string,
-                                         const Extension* extension);
+      const extensions::Extension* extension);
 
   // Returns true if |url| is used for testing crashes.
   static bool IsCrashURL(const GURL& url);