Add autofill metrics to dig into the failure case.

chrome/browser/autofill/form_structure.h

 // Copyright (c) 2009 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_AUTOFILL_FORM_STRUCTURE_H_
 #define CHROME_BROWSER_AUTOFILL_FORM_STRUCTURE_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 20 matching lines @@
   USE_UPLOAD_RATES
 };
 
 class AutoFillMetrics;
 
 // FormStructure stores a single HTML form together with the values entered
 // in the fields along with additional information needed by AutoFill.
 class FormStructure {
  public:
   explicit FormStructure(const webkit_glue::FormData& form);
-  ~FormStructure();
+  virtual ~FormStructure();
 
   // Encodes the XML upload request from this FormStructure.
   bool EncodeUploadRequest(bool auto_fill_used,
                            std::string* encoded_xml) const;
 
   // Encodes the XML query request for the set of forms.
   // All fields are returned in one XML. For example, there are three forms,
   // with 2, 4, and 3 fields. The returned XML would have type info for 9
   // fields, first two of which would be for the first form, next 4 for the
   // second, and the rest is for the third.
@@ skipping 47 matching lines @@
   }
   std::vector<AutoFillField*>::const_iterator end() const {
     return fields_.end();
   }
 
   const GURL& source_url() const { return source_url_; }
 
   bool operator==(const webkit_glue::FormData& form) const;
   bool operator!=(const webkit_glue::FormData& form) const;
 
+ protected:
+  // For tests.
+  ScopedVector<AutoFillField>* fields() { return &fields_; }
+
  private:
   enum EncodeRequestType {
     QUERY,
     UPLOAD,
   };
 
   // Runs several heuristics against the form fields to determine their possible
   // types.
   void GetHeuristicAutoFillTypes();
 
@@ skipping 30 matching lines @@
   // character. E.g.: "&form_input1_name&form_input2_name&...&form_inputN_name"
   std::string form_signature_field_names_;
 
   // GET or POST.
   RequestMethod method_;
 
   DISALLOW_COPY_AND_ASSIGN(FormStructure);
 };
 
 #endif  // CHROME_BROWSER_AUTOFILL_FORM_STRUCTURE_H_