Implement WebViewDatabase's hasFormData API for chromium based webview.

components/autofill/browser/webdata/autofill_webdata.h

Index: components/autofill/browser/webdata/autofill_webdata.h
diff --git a/components/autofill/browser/webdata/autofill_webdata.h b/components/autofill/browser/webdata/autofill_webdata.h
index 032649b5241fe10fe5f3ed690f0683f13f7eac14..66f42f8d50a7dedc1dbcb4f8c83450cab680522b 100644
--- a/components/autofill/browser/webdata/autofill_webdata.h
+++ b/components/autofill/browser/webdata/autofill_webdata.h
@@ -41,6 +41,10 @@ class AutofillWebData {
       int limit,
       WebDataServiceConsumer* consumer) = 0;
 
+  // Checks if there are any form elements in the database.
+  virtual WebDataServiceBase::Handle HasFormElements(
+      WebDataServiceConsumer* consumer) = 0;
+
   // Removes form elements recorded for Autocomplete from the database.
   virtual void RemoveFormElementsAddedBetween(
       const base::Time& delete_begin, const base::Time& delete_end) = 0;