Add upstream bits necessary for iOS card unmask prompt.

components/autofill/ios/browser/js_autofill_manager.mm

 // Copyright 2013 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.
 
 #import "components/autofill/ios/browser/js_autofill_manager.h"
 
 #include "base/format_macros.h"
 #include "base/json/string_escape.h"
 #include "base/logging.h"
 
@@ skipping 29 matching lines @@
 #pragma mark ProtectedMethods
 
 - (NSString*)scriptPath {
   return @"autofill_controller";
 }
 
 - (NSString*)presenceBeacon {
   return @"__gCrWeb.autofill";
 }
 
+- (void)storeActiveElement {
+  NSString* js = @"__gCrWeb.autofill.storeActiveElement()";
+  [self evaluate:js stringResultHandler:nil];
+}
+
 - (void)fillActiveFormField:(NSString*)dataString
           completionHandler:(ProceduralBlock)completionHandler {
   web::JavaScriptCompletion resultHandler = ^void(NSString*, NSError*) {
     completionHandler();
   };
 
   NSString* js =
       [NSString stringWithFormat:@"__gCrWeb.autofill.fillActiveFormField(%@);",
                                  dataString];
   [self evaluate:js stringResultHandler:resultHandler];
@@ skipping 29 matching lines @@
 }
 
 - (void)fillPredictionData:(NSString*)dataString {
   [self deferredEvaluate:
             [NSString
                 stringWithFormat:@"__gCrWeb.autofill.fillPredictionData(%@);",
                                  dataString]];
 }
 
 @end