Move small c/b/extensions classes into extensions namespace no.1

chrome/browser/ui/webui/extensions/extension_activity_ui.cc

Index: chrome/browser/ui/webui/extensions/extension_activity_ui.cc
diff --git a/chrome/browser/ui/webui/extensions/extension_activity_ui.cc b/chrome/browser/ui/webui/extensions/extension_activity_ui.cc
index fa69c771561579a28cd305b59d541c63ec4c7d09..93dd822733ee9dce50677ccb24bd144c72e79342 100644
--- a/chrome/browser/ui/webui/extensions/extension_activity_ui.cc
+++ b/chrome/browser/ui/webui/extensions/extension_activity_ui.cc
@@ -52,7 +52,7 @@ ExtensionActivityUI::ExtensionActivityUI(content::WebUI* web_ui)
 
 ExtensionActivityUI::~ExtensionActivityUI() {
   if (extension_)
-    ExtensionActivityLog::GetInstance()->RemoveObserver(extension_, this);
+    extensions::ActivityLog::GetInstance()->RemoveObserver(extension_, this);
 }
 
 void ExtensionActivityUI::HandleRequestExtensionData(
@@ -88,12 +88,12 @@ void ExtensionActivityUI::HandleRequestExtensionData(
   web_ui()->CallJavascriptFunction("extension_activity.handleExtensionData",
                                    result);
 
-  ExtensionActivityLog::GetInstance()->AddObserver(extension_, this);
+  extensions::ActivityLog::GetInstance()->AddObserver(extension_, this);
 }
 
 void ExtensionActivityUI::OnExtensionActivity(
       const extensions::Extension* extension,
-      ExtensionActivityLog::Activity activity,
+      extensions::ActivityLog::Activity activity,
       const std::string& msg) {
   DictionaryValue result;
   result.SetInteger("activity", activity);