[New Tab Page] Change the mechanism to intercept online NTP errors

chrome/browser/ui/search/new_tab_page_interceptor_service.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_SEARCH_NEW_TAB_PAGE_INTERCEPTOR_SERVICE_H_
+#define CHROME_BROWSER_UI_SEARCH_NEW_TAB_PAGE_INTERCEPTOR_SERVICE_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "components/search_engines/template_url_service_observer.h"
+#include "net/url_request/url_request_interceptor.h"
+#include "url/gurl.h"
+
+class NewTabPageInterceptor;
+class Profile;
+class TemplateURLService;
+
+namespace net {
+class URLRequestInterceptor;
+}
+
+// Owns a NewTabPageInterceptor.
+class NewTabPageInterceptorService : public KeyedService,
+                                     public TemplateURLServiceObserver {
+ public:
+  explicit NewTabPageInterceptorService(Profile* profile);
+  ~NewTabPageInterceptorService() override;
+
+  // TemplateURLServiceObserver override.
+  void OnTemplateURLServiceChanged() override;
+
+  scoped_ptr<net::URLRequestInterceptor> CreateInterceptor();
+
+ private:
+  // Implementation of the URLRequestInterceptor for the New Tab Page. Will look
+  // at incoming response from the server and possibly divert to the local NTP.
+  class NewTabPageInterceptor : public net::URLRequestInterceptor {

[mmenke, 2015/01/22 20:53:51]

I'd suggest just forward declaring the class here, and moving the definition
into the header file, too, to reduce stuff in the header and remove an include
or two from it as well (url_request_interceptor.h and gurl.h).

[Mathieu, 2015/01/22 21:44:22]

Done. Have a look!

+   public:
+    explicit NewTabPageInterceptor(const GURL& new_tab_url);
+
+    ~NewTabPageInterceptor() override;
+
+    base::WeakPtr<NewTabPageInterceptor> GetWeakPtr();
+
+    void SetNewTabPageURL(const GURL& new_tab_page_url);
+
+   private:
+    // Overrides from net::URLRequestInterceptor:
+    net::URLRequestJob* MaybeInterceptRequest(
+        net::URLRequest* request,
+        net::NetworkDelegate* network_delegate) const override;
+    net::URLRequestJob* MaybeInterceptResponse(
+        net::URLRequest* request,
+        net::NetworkDelegate* network_delegate) const override;
+
+    GURL new_tab_url_;
+    base::WeakPtrFactory<NewTabPageInterceptor> weak_factory_;
+
+    DISALLOW_COPY_AND_ASSIGN(NewTabPageInterceptor);
+  };
+
+  Profile* profile_;
+  base::WeakPtr<NewTabPageInterceptor> interceptor_;
+  // The TemplateURLService that we are observing. It will outlive this
+  // NewTabPageInterceptorService due to the dependency declared in
+  // NewTabPageInterceptorServiceFactory.
+  TemplateURLService* template_url_service_;
+
+  DISALLOW_COPY_AND_ASSIGN(NewTabPageInterceptorService);
+};
+
+#endif  // CHROME_BROWSER_UI_SEARCH_NEW_TAB_PAGE_INTERCEPTOR_SERVICE_H_