Refactoring: de-couple Extensions from "script injection System" [render side]:3

extensions/renderer/extension_injection_host.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/common/manifest_handlers/csp_info.h"
 #include "extensions/renderer/extension_injection_host.h"
 
 namespace extensions {
 
 ExtensionInjectionHost::ExtensionInjectionHost(
     const scoped_refptr<const Extension>& extension)
     : InjectionHost(HostID(HostID::EXTENSIONS, extension->id())),
       extension_(extension) {
 }
 
 ExtensionInjectionHost::~ExtensionInjectionHost() {
 }
 
-const std::string& ExtensionInjectionHost::GetContentSecurityPolicy() const {
+std::string ExtensionInjectionHost::GetContentSecurityPolicy() const {
   return CSPInfo::GetContentSecurityPolicy(extension_.get());
 }
 
 const GURL& ExtensionInjectionHost::url() const {
   return extension_->url();
 }
 
 const std::string& ExtensionInjectionHost::name() const {
   return extension_->name();
 }
@@ skipping 18 matching lines @@
     return extension_->permissions_data()->GetContentScriptAccess(
         extension_.get(),
         document_url,
         top_frame_url,
         tab_id,
         -1,  // no process id
         nullptr /* ignore error */);
   }
 }
 
+bool ExtensionInjectionHost::IsGone() const {
+  return extension_.get() == nullptr;
+}
+
 }  // namespace extensions