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

chrome/browser/ui/search/new_tab_page_interceptor_service.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 "chrome/browser/ui/search/new_tab_page_interceptor_service.h"
+
+#include "base/location.h"
+#include "base/metrics/histogram.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/search/search.h"
+#include "chrome/browser/search_engines/template_url_service_factory.h"
+#include "chrome/common/url_constants.h"
+#include "components/search_engines/template_url_service.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/base/net_errors.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_job.h"
+#include "net/url_request/url_request_redirect_job.h"
+
+NewTabPageInterceptorService::NewTabPageInterceptor::NewTabPageInterceptor(
+    const GURL& new_tab_url)
+    : new_tab_url_(new_tab_url), weak_factory_(this) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+}
+
+NewTabPageInterceptorService::NewTabPageInterceptor::~NewTabPageInterceptor() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+}
+
+base::WeakPtr<NewTabPageInterceptorService::NewTabPageInterceptor>
+NewTabPageInterceptorService::NewTabPageInterceptor::GetWeakPtr() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  return weak_factory_.GetWeakPtr();
+}
+
+void NewTabPageInterceptorService::NewTabPageInterceptor::SetNewTabPageURL(
+    const GURL& new_tab_page_url) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  new_tab_url_ = new_tab_page_url;
+}
+
+net::URLRequestJob*
+NewTabPageInterceptorService::NewTabPageInterceptor::MaybeInterceptRequest(
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate) const {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  return nullptr;
+}
+
+net::URLRequestJob*
+NewTabPageInterceptorService::NewTabPageInterceptor::MaybeInterceptResponse(
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate) const {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  if ((request->url() != new_tab_url_) ||
+      (new_tab_url_ == GURL(chrome::kChromeSearchLocalNtpUrl))) {
+    return nullptr;
+  }
+  // User has canceled this navigation so it shouldn't be redirected.
+  if (request->status().status() == net::URLRequestStatus::CANCELED ||
+      (request->status().status() == net::URLRequestStatus::FAILED &&
+       request->status().error() == net::ERR_ABORTED)) {
+    return nullptr;
+  }
+
+  // Request to NTP was successful.
+  if (request->status().is_success() &&
+      request->GetResponseCode() != net::HTTP_NO_CONTENT &&
+      request->GetResponseCode() < 400)
+    return nullptr;

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

nit:  Use braces when the if body takes more than one line

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

Done.

+
+  // Failure to load the NTP correctly; redirect to Local NTP.
+  UMA_HISTOGRAM_ENUMERATION("InstantExtended.CacheableNTPLoad",
+                            chrome::CACHEABLE_NTP_LOAD_FAILED,
+                            chrome::CACHEABLE_NTP_LOAD_MAX);
+  return new net::URLRequestRedirectJob(
+      request, network_delegate, GURL(chrome::kChromeSearchLocalNtpUrl),
+      net::URLRequestRedirectJob::REDIRECT_307_TEMPORARY_REDIRECT,
+      "NTP Request Interceptor");
+}
+
+NewTabPageInterceptorService::NewTabPageInterceptorService(Profile* profile)
+    : profile_(profile),
+      template_url_service_(TemplateURLServiceFactory::GetForProfile(profile)) {
+  DCHECK(profile_);

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

nit:  include base/logging.h for DCHECK

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

Done.

+  if (template_url_service_)
+    template_url_service_->AddObserver(this);
+}
+
+NewTabPageInterceptorService::~NewTabPageInterceptorService() {
+  if (template_url_service_)
+    template_url_service_->RemoveObserver(this);
+}
+
+void NewTabPageInterceptorService::OnTemplateURLServiceChanged() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  GURL new_tab_page_url(chrome::GetNewTabPageURL(profile_));
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&NewTabPageInterceptor::SetNewTabPageURL, interceptor_,
+                 new_tab_page_url));
+}
+
+scoped_ptr<net::URLRequestInterceptor>
+NewTabPageInterceptorService::CreateInterceptor() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  scoped_ptr<NewTabPageInterceptor> interceptor(
+      new NewTabPageInterceptor(chrome::GetNewTabPageURL(profile_)));
+  interceptor_ = interceptor->GetWeakPtr();
+  return interceptor.Pass();
+}