Implement WebViewDatabase's hasFormData API for chromium based webview.

components/autofill/browser/webdata/autofill_table.h

Index: components/autofill/browser/webdata/autofill_table.h
diff --git a/components/autofill/browser/webdata/autofill_table.h b/components/autofill/browser/webdata/autofill_table.h
index f86302f89f70e53b641829f6b1b9c395af509a8a..0ff0c8fd0ce90c7aafb9b159d6dd497011a2b80c 100644
--- a/components/autofill/browser/webdata/autofill_table.h
+++ b/components/autofill/browser/webdata/autofill_table.h
@@ -154,6 +154,9 @@ class AutofillTable : public WebDatabaseTable {
                                    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