Display DNS probe results.

chrome/browser/net/net_error_tab_helper.h

 // Copyright (c) 2012 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_NET_NET_ERROR_TAB_HELPER_H_
 #define CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
 
 #include "base/basictypes.h"
+#include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_member.h"
 #include "chrome/browser/net/dns_probe_service.h"
 #include "chrome/common/net/net_error_info.h"
-#include "chrome/common/net/net_error_tracker.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace chrome_browser_net {
 
 // A TabHelper that monitors loads for certain types of network errors and
 // does interesting things with them.  Currently, starts DNS probes using the
 // DnsProbeService whenever a page fails to load with a DNS-related error.
 class NetErrorTabHelper
     : public content::WebContentsObserver,
       public content::WebContentsUserData<NetErrorTabHelper> {
  public:
   enum TestingState {
     TESTING_DEFAULT,
     TESTING_FORCE_DISABLED,
     TESTING_FORCE_ENABLED
   };
 
+  typedef base::Callback<void(chrome_common_net::DnsProbeStatus)>
+      NetErrorInfoSnoopCallback;

[mmenke, 2013/06/24 16:20:00]

Since this takes a DnsProbeStatus rather than a NetErrorInfo, I think this
naming is confusing.  Fine with either renaming it, or changing its argument
type.

[Deprecated (see juliatuttle), 2013/06/25 16:45:04]

There is no such type as a NetErrorInfo; I'll rename it to
DnsProbeStatusSnoopCallback.

[mmenke, 2013/06/25 17:40:26]

There is actually a "ChromeViewMsg_NetErrorInfo", which could theoretically be
referred to as "NetErrorInfo".  From the old function name, that's what I
expected it to take as an argument.

+
   virtual ~NetErrorTabHelper();
 
   static void set_state_for_testing(TestingState testing_state);
 
+  // Sets a callback that will be called immediately after the helper sends
+  // a NetErrorHelper IPC.  (Used by the DNS probe browser test to know when to
+  // check the error page for updates, instead of polling.)
+  void set_net_error_info_snoop_callback_for_testing(
+      const NetErrorInfoSnoopCallback& net_error_snoop_callback);

[mmenke, 2013/06/24 16:20:00]

Per Google style guide, functions that use this naming scheme should be inlined.
 I'm not actually sure about the overhead of copying a callback, though I
believe the data they hold is actually refcounted, so a "copy" is just
incrementing a reference and copying a pointer.

[Deprecated (see juliatuttle), 2013/06/25 16:45:04]

Done.

+
   // content::WebContentsObserver implementation.
   virtual void DidStartProvisionalLoadForFrame(
       int64 frame_id,
       int64 parent_frame_id,
       bool is_main_frame,
       const GURL& validated_url,
       bool is_error_page,
       bool is_iframe_srcdoc,
       content::RenderViewHost* render_view_host) OVERRIDE;
 
   virtual void DidCommitProvisionalLoadForFrame(
       int64 frame_id,
       bool is_main_frame,
       const GURL& url,
       content::PageTransition transition_type,
       content::RenderViewHost* render_view_host) OVERRIDE;
 
   virtual void DidFailProvisionalLoad(
       int64 frame_id,
       bool is_main_frame,
       const GURL& validated_url,
       int error_code,
       const string16& error_description,
       content::RenderViewHost* render_view_host) OVERRIDE;
 
-  virtual void DidFinishLoad(
-      int64 frame_id,
-      const GURL& validated_url,
-      bool is_main_frame,
-      content::RenderViewHost* render_view_host) OVERRIDE;
+ protected:
+  // |contents| is the WebContents of the tab this NetErrorTabHelper is
+  // attached to.
+  explicit NetErrorTabHelper(content::WebContents* contents);
+  virtual void StartDnsProbe();
+  virtual void SendInfo();
+  void OnDnsProbeFinished(chrome_common_net::DnsProbeStatus result);
+
+  // The status of a DNS probe that may or may not have started or finished.
+  // Since the renderer can change out from under the helper (in cross-process
+  // navigations), it re-sends the status whenever an error page commits.
+  chrome_common_net::DnsProbeStatus dns_probe_status_;
 
  private:
   friend class content::WebContentsUserData<NetErrorTabHelper>;
 
-  enum DnsProbeState {
-    DNS_PROBE_NONE,
-    DNS_PROBE_STARTED,
-    DNS_PROBE_FINISHED
-  };
-
-  // |contents| is the WebContents of the tab this NetErrorTabHelper is
-  // attached to.
-  explicit NetErrorTabHelper(content::WebContents* contents);
-
-  void TrackerCallback(NetErrorTracker::DnsErrorPageState state);
-  void MaybePostStartDnsProbeTask();
-  void OnDnsProbeFinished(chrome_common_net::DnsProbeResult result);
-  void MaybeSendInfo();
+  void OnMainFrameDnsError();
 
   void InitializePref(content::WebContents* contents);
   bool ProbesAllowed() const;
 
   base::WeakPtrFactory<NetErrorTabHelper> weak_factory_;
 
-  NetErrorTracker tracker_;
-  NetErrorTracker::DnsErrorPageState dns_error_page_state_;
+  // True if the last provisional load that started was for an error page.
+  bool is_error_page_;
 
-  DnsProbeState dns_probe_state_;
-  chrome_common_net::DnsProbeResult dns_probe_result_;
+  // True if the helper has seen a main frame page load fail with a DNS error,
+  // but has not yet seen a new page load successfully afterwards.
+  bool dns_error_active_;
 
   // Whether we are enabled to run by the DnsProbe-Enable field trial.
   const bool enabled_by_trial_;
+
+  // Optional callback for browser test to snoop on outgoing NetErrorInfo IPCs.
+  NetErrorInfoSnoopCallback net_error_info_snoop_callback_;
+
   // "Use a web service to resolve navigation errors" preference is required
   // to allow probes.
   BooleanPrefMember resolve_errors_with_web_service_;
 
   DISALLOW_COPY_AND_ASSIGN(NetErrorTabHelper);
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_