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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 DidStartProvisionalLoadForFrame(
     50       int64 frame_id,
     51       int64 parent_frame_id,
     52       bool is_main_frame,
     53       const GURL& validated_url,
     54       bool is_error_page,
     55       bool is_iframe_srcdoc,
     56       content::RenderViewHost* render_view_host) OVERRIDE;
     57 
     58   virtual void DidCommitProvisionalLoadForFrame(
     59       int64 frame_id,
     60       bool is_main_frame,
     61       const GURL& url,
     62       content::PageTransition transition_type,
     63       content::RenderViewHost* render_view_host) OVERRIDE;
     64 
     65   virtual void DidFailProvisionalLoad(
     66       int64 frame_id,
     67       bool is_main_frame,
     68       const GURL& validated_url,
     69       int error_code,
     70       const string16& error_description,
     71       content::RenderViewHost* render_view_host) OVERRIDE;
     72 
     73  protected:
     74   // |contents| is the WebContents of the tab this NetErrorTabHelper is
     75   // attached to.
     76   explicit NetErrorTabHelper(content::WebContents* contents);
     77   virtual void StartDnsProbe();
     78   virtual void SendInfo();
     79   void OnDnsProbeFinished(chrome_common_net::DnsProbeStatus result);
     80 
     81   chrome_common_net::DnsProbeStatus dns_probe_status() const {
     82     return dns_probe_status_;
     83   }
     84 
     85  private:
     86   friend class content::WebContentsUserData<NetErrorTabHelper>;
     87 
     88   void OnMainFrameDnsError();
     89 
     90   void InitializePref(content::WebContents* contents);
     91   bool ProbesAllowed() const;
     92 
     93   base::WeakPtrFactory<NetErrorTabHelper> weak_factory_;
     94 
     95   // True if the last provisional load that started was for an error page.
     96   bool is_error_page_;
     97 
     98   // True if the helper has seen a main frame page load fail with a DNS error,
     99   // but has not yet seen a new page commit successfully afterwards.
    100   bool dns_error_active_;
    101 
    102   // True if the helper has seen an error page commit while |dns_error_active_|
    103   // is true.  (This should never be true if |dns_error_active_| is false.)
    104   bool dns_error_page_committed_;
    105 
    106   // The status of a DNS probe that may or may not have started or finished.
    107   // Since the renderer can change out from under the helper (in cross-process
    108   // navigations), it re-sends the status whenever an error page commits.
    109   chrome_common_net::DnsProbeStatus dns_probe_status_;
    110 
    111   // Whether probes are enabled (by the command-line option or the field trial).
    112   const bool probes_enabled_;
    113 
    114   // Optional callback for browser test to snoop on outgoing NetErrorInfo IPCs.
    115   DnsProbeStatusSnoopCallback dns_probe_status_snoop_callback_;
    116 
    117   // "Use a web service to resolve navigation errors" preference is required
    118   // to allow probes.
    119   BooleanPrefMember resolve_errors_with_web_service_;
    120 
    121   DISALLOW_COPY_AND_ASSIGN(NetErrorTabHelper);
    122 };
    123 
    124 }  // namespace chrome_browser_net
    125 
    126 #endif  // CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
    127