Make WebUI webview content script work with incognito.

extensions/browser/declarative_user_script_manager.cc

Index: extensions/browser/declarative_user_script_manager.cc
diff --git a/extensions/browser/declarative_user_script_manager.cc b/extensions/browser/declarative_user_script_manager.cc
index 3b6c4c7a470d36bd2483a65a14bf87372dd61b81..bd26ddad689ad01a749a48c71bf4034ce8763b42 100644
--- a/extensions/browser/declarative_user_script_manager.cc
+++ b/extensions/browser/declarative_user_script_manager.cc
@@ -22,20 +22,26 @@ DeclarativeUserScriptManager::~DeclarativeUserScriptManager() {
 DeclarativeUserScriptMaster*
 DeclarativeUserScriptManager::GetDeclarativeUserScriptMasterByID(
     const HostID& host_id) {
+  return GetDeclarativeUserScriptMasterByID(browser_context_, host_id);
+}
+
+DeclarativeUserScriptMaster*
+DeclarativeUserScriptManager::GetDeclarativeUserScriptMasterByID(
+    content::BrowserContext* browser_context, const HostID& host_id) {
   UserScriptMasterMap::iterator it =
       declarative_user_script_masters_.find(host_id);
 
   if (it != declarative_user_script_masters_.end())
     return it->second.get();
 
-  return CreateDeclarativeUserScriptMaster(host_id);
+  return CreateDeclarativeUserScriptMaster(browser_context, host_id);
 }
 
 DeclarativeUserScriptMaster*
 DeclarativeUserScriptManager::CreateDeclarativeUserScriptMaster(
-    const HostID& host_id) {
+    content::BrowserContext* browser_context, const HostID& host_id) {
   linked_ptr<DeclarativeUserScriptMaster> master(
-      new DeclarativeUserScriptMaster(browser_context_, host_id));
+      new DeclarativeUserScriptMaster(browser_context, host_id));
   declarative_user_script_masters_[host_id] = master;
   return master.get();
 }