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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
      6 #define CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/bind.h"
     10 #include "base/compiler_specific.h"
     11 #include "base/memory/weak_ptr.h"
     12 #include "base/prefs/pref_member.h"
     13 #include "chrome/browser/net/dns_probe_service.h"
     14 #include "chrome/common/net/net_error_info.h"
     15 #include "content/public/browser/web_contents_observer.h"
     16 #include "content/public/browser/web_contents_user_data.h"
     17 
     18 namespace chrome_browser_net {
     19 
     20 // A TabHelper that monitors loads for certain types of network errors and
     21 // does interesting things with them.  Currently, starts DNS probes using the
     22 // DnsProbeService whenever a page fails to load with a DNS-related error.
     23 class NetErrorTabHelper
     24     : public content::WebContentsObserver,
     25       public content::WebContentsUserData<NetErrorTabHelper> {
     26  public:
     27   enum TestingState {
     28     TESTING_DEFAULT,
     29     TESTING_FORCE_DISABLED,
     30     TESTING_FORCE_ENABLED
     31   };
     32 
     33   typedef base::Callback<void(chrome_common_net::DnsProbeStatus)>
     34       DnsProbeStatusSnoopCallback;
     35 
     36   virtual ~NetErrorTabHelper();
     37 
     38   static void set_state_for_testing(TestingState testing_state);
     39 
     40   // Sets a callback that will be called immediately after the helper sends
     41   // a NetErrorHelper IPC.  (Used by the DNS probe browser test to know when to
     42   // check the error page for updates, instead of polling.)
     43   void set_dns_probe_status_snoop_callback_for_testing(
     44       const DnsProbeStatusSnoopCallback& dns_probe_status_snoop_callback) {
     45     dns_probe_status_snoop_callback_ = dns_probe_status_snoop_callback;
     46   }
     47 
     48   // content::WebContentsObserver implementation.
     49   virtual void DidStartNavigationToPendingEntry(
     50       const GURL& url,
     51       content::NavigationController::ReloadType reload_type) OVERRIDE;
     52 
     53   virtual void DidStartProvisionalLoadForFrame(
     54       content::RenderFrameHost* render_frame_host,
     55       const GURL& validated_url,
     56       bool is_error_page,
     57       bool is_iframe_srcdoc) OVERRIDE;
     58 
     59   virtual void DidCommitProvisionalLoadForFrame(
     60       content::RenderFrameHost* render_frame_host,
     61       const GURL& url,
     62       ui::PageTransition transition_type) OVERRIDE;
     63 
     64   virtual void DidFailProvisionalLoad(
     65       content::RenderFrameHost* render_frame_host,
     66       const GURL& validated_url,
     67       int error_code,
     68       const base::string16& error_description) OVERRIDE;
     69 
     70  protected:
     71   // |contents| is the WebContents of the tab this NetErrorTabHelper is
     72   // attached to.
     73   explicit NetErrorTabHelper(content::WebContents* contents);
     74   virtual void StartDnsProbe();
     75   virtual void SendInfo();
     76   void OnDnsProbeFinished(chrome_common_net::DnsProbeStatus result);
     77 
     78   chrome_common_net::DnsProbeStatus dns_probe_status() const {
     79     return dns_probe_status_;
     80   }
     81 
     82  private:
     83   friend class content::WebContentsUserData<NetErrorTabHelper>;
     84 
     85   void OnMainFrameDnsError();
     86 
     87   void InitializePref(content::WebContents* contents);
     88   bool ProbesAllowed() const;
     89 
     90   // True if the last provisional load that started was for an error page.
     91   bool is_error_page_;
     92 
     93   // True if the helper has seen a main frame page load fail with a DNS error,
     94   // but has not yet seen a new page commit successfully afterwards.
     95   bool dns_error_active_;
     96 
     97   // True if the helper has seen an error page commit while |dns_error_active_|
     98   // is true.  (This should never be true if |dns_error_active_| is false.)
     99   bool dns_error_page_committed_;
    100 
    101   // The status of a DNS probe that may or may not have started or finished.
    102   // Since the renderer can change out from under the helper (in cross-process
    103   // navigations), it re-sends the status whenever an error page commits.
    104   chrome_common_net::DnsProbeStatus dns_probe_status_;
    105 
    106   // Optional callback for browser test to snoop on outgoing NetErrorInfo IPCs.
    107   DnsProbeStatusSnoopCallback dns_probe_status_snoop_callback_;
    108 
    109   // "Use a web service to resolve navigation errors" preference is required
    110   // to allow probes.
    111   BooleanPrefMember resolve_errors_with_web_service_;
    112 
    113   base::WeakPtrFactory<NetErrorTabHelper> weak_factory_;
    114 
    115   DISALLOW_COPY_AND_ASSIGN(NetErrorTabHelper);
    116 };
    117 
    118 }  // namespace chrome_browser_net
    119 
    120 #endif  // CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
    121