Implement WebViewDatabase's hasFormData API for chromium based webview.

components/autofill/browser/webdata/autofill_table.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 COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_TABLE_H_
 #define COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_TABLE_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
@@ skipping 136 matching lines @@
                          std::vector<AutofillChange>* changes);
 
   // Retrieves a vector of all values which have been recorded in the autofill
   // table as the value in a form element with name |name| and which start with
   // |prefix|.  The comparison of the prefix is case insensitive.
   bool GetFormValuesForElementName(const base::string16& name,
                                    const base::string16& prefix,
                                    std::vector<base::string16>* values,
                                    int limit);
 
+  // Returns whether any form elements are stored in the database.
+  bool HasFormElements();
+
   // Removes rows from autofill_dates if they were created on or after
   // |delete_begin| and strictly before |delete_end|.  Decrements the
   // count of the corresponding rows in the autofill table, and
   // removes those rows if the count goes to 0.  A list of all changed
   // keys and whether each was updater or removed is returned in the
   // changes out parameter.
   bool RemoveFormElementsAddedBetween(const base::Time& delete_begin,
                                       const base::Time& delete_end,
                                       std::vector<AutofillChange>* changes);
 
@@ skipping 201 matching lines @@
   // created (on the UI thread), and cached here so that it can be used for
   // migrations (on the DB thread).
   std::string app_locale_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillTable);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_TABLE_H_