Display DNS probe results.

chrome/renderer/net/net_error_helper.h

Index: chrome/renderer/net/net_error_helper.h
diff --git a/chrome/renderer/net/net_error_helper.h b/chrome/renderer/net/net_error_helper.h
index cb33387e1e19cb9baee021c56909020cf0fc53d3..f5ffdbeb9bb19c0a6921408c1b681435eac87526 100644
--- a/chrome/renderer/net/net_error_helper.h
+++ b/chrome/renderer/net/net_error_helper.h
@@ -5,14 +5,23 @@
 #ifndef CHROME_RENDERER_NET_NET_ERROR_HELPER_H_
 #define CHROME_RENDERER_NET_NET_ERROR_HELPER_H_
 
+#include <string>
+
 #include "chrome/common/net/net_error_info.h"
-#include "chrome/common/net/net_error_tracker.h"
 #include "content/public/renderer/render_view_observer.h"
+#include "third_party/WebKit/public/platform/WebURLError.h"
+
+namespace base {
+class DictionaryValue;
+}
 
 namespace WebKit {
 class WebFrame;
 }
 
+// Listens for NetErrorInfo messages from the NetErrorTabHelper on the
+// browser side and updates the error page with more details (currently, just
+// DNS probe results) if/when available.
 class NetErrorHelper : public content::RenderViewObserver {
  public:
   explicit NetErrorHelper(content::RenderView* render_view);
@@ -31,14 +40,56 @@ class NetErrorHelper : public content::RenderViewObserver {
   // IPC::Listener implementation.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
+  static bool GetErrorStringsForDnsProbe(

[mmenke, 2013/06/28 18:06:19]

Think this needs a comment.

+      WebKit::WebFrame* frame,
+      const WebKit::WebURLError& error,
+      bool is_failed_post,
+      const std::string& locale,
+      base::DictionaryValue* error_strings);
+
+ protected:
+  // These methods handle tracking the actual state of the page; this allows
+  // unit-testing of the state tracking without having to mock out WebFrames
+  // and such.
+  void OnStartLoad(bool is_main_frame, bool is_error_page);
+  void OnFailLoad(bool is_main_frame, bool is_dns_error);
+  void OnCommitLoad(bool is_main_frame);
+  void OnFinishLoad(bool is_main_frame);
+
+  void OnNetErrorInfo(int status);
+  virtual void UpdateErrorPage();
+
+  // The last DnsProbeStatus received from the browser.
+  chrome_common_net::DnsProbeStatus last_probe_status_;
+
  private:
-  void OnNetErrorInfo(int dns_probe_result);
-  void TrackerCallback(NetErrorTracker::DnsErrorPageState state);
-  void UpdateErrorPage(chrome_common_net::DnsProbeResult dns_probe_result);
+  WebKit::WebURLError GetUpdatedError() const;
+
+  // Whether the last provisional load started was for an error page.
+  bool last_start_was_error_page_;
+
+  // Whether the last provisional load failure failed with a DNS error.
+  bool last_fail_was_dns_error_;
+
+  // This is an odd variable.
+  //
+  // Ideally, it would be simply "last_commit_was_dns_error_page_".
+  //
+  // Unfortunately, that breaks if two DNS errors occur in a row; after the
+  // second failure, but before the second page commits, the helper can receive
+  // probe results.  If all it knows is that the last commit was a DNS error
+  // page, it will cheerfully forward the results for the second probe to the
+  // first page.
+  //
+  // Thus, the semantics of this flag are a little weird.  It is set whenever
+  // a DNS error page commits, and cleared whenever any other page commits,
+  // but it is also cleared whenever a DNS error occurs, to prevent the race
+  // described above.
+  bool forwarding_probe_results_;
+
+  // The last main frame error seen by the helper.
+  WebKit::WebURLError last_error_;
 
-  NetErrorTracker tracker_;
-  NetErrorTracker::DnsErrorPageState dns_error_page_state_;
-  bool updated_error_page_;
   bool is_failed_post_;
 };