[Password Generation] Enable generation for dynamically created forms.

chrome/renderer/autofill/password_generation_agent_browsertest.cc

 // 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.
 
 #include <string.h>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/histogram_tester.h"
 #include "chrome/test/base/chrome_render_view_test.h"
@@ skipping 325 matching lines @@
   // Loading a different page triggers UMA stat upload. Verify that only one
   // display event is sent even though
   LoadHTML(kSigninFormHTML);
 
   histogram_tester.ExpectBucketCount(
       "PasswordGeneration.Event",
       autofill::password_generation::GENERATION_POPUP_SHOWN,
       1);
 }
 
+TEST_F(PasswordGenerationAgentTest, DynamicFormTest) {
+  LoadHTML(kSigninFormHTML);
+  SetNotBlacklistedMessage(kSigninFormHTML);
+  SetAccountCreationFormsDetectedMessage(kSigninFormHTML);
+
+  ExecuteJavaScript(
+      "var form = document.createElement('form');"
+      "var username = document.createElement('input');"
+      "username.type = 'text';"
+      "username.id = 'dynamic_username';"
+      "var first_password = document.createElement('input');"
+      "first_password.type = 'password';"
+      "first_password.id = 'first_password';"
+      "first_password.name = 'first_password';"
+      "var second_password = document.createElement('input');"
+      "second_password.type = 'password';"
+      "second_password.id = 'second_password';"
+      "second_password.name = 'second_password';"
+      "form.appendChild(username);"
+      "form.appendChild(first_password);"
+      "form.appendChild(second_password);"
+      "document.body.appendChild(form);");
+  ProcessPendingMessages();

[Garrett Casto, 2014/10/15 22:11:45]

I'm slightly worried that this might flake because the timing of when
didAssociateFormControls() is run is not something that I understand perfectly.
I could explicitly call OnDynamicFormsSeen(GetMainFrame()), but that makes the
test weaker. I can go either way on this.

[vabr (Chromium), 2014/10/16 07:46:15]

If it does not flake during tryjobs and in the tree right after commit, I would
try the current version. But it may be helpful to add a code comment roughly
saying the same as you review comment here, to help fix the situation quickly if
the flakes occur.

[Garrett Casto, 2014/10/16 19:14:06]

Added a comment. I've run this over 200 times locally and it seems fine, but
there are some flakes that I've never been able to reproduce locally so still
might be a problem.

+  ExpectPasswordGenerationAvailable("first_password", true);
+}
+
 }  // namespace autofill