Added UMA statistics for change passwords in the Password Manager

chrome/browser/ui/views/passwords/manage_passwords_bubble_view.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 "chrome/browser/ui/views/passwords/manage_passwords_bubble_view.h"
 
 #include "base/timer/timer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
@@ skipping 1009 matching lines @@
   SetLayoutManager(layout);
 
   // Create the pending credential item, update button.
   View* item = nullptr;
   if (parent->model()->ShouldShowMultipleAccountUpdateUI()) {
     selection_view_ = new CredentialsSelectionView(
         parent->model(), parent->model()->local_credentials().get(),
         parent->model()->pending_password().username_value);
     item = selection_view_;
   } else {
-    DCHECK_EQ(1u, parent->model()->local_credentials().size());

[dvadym, 2015/08/19 11:47:56]

Since https://codereview.chromium.org/1297963002/ it's legitimate case when he
have more than 1 local_credentials and 1 account bubble because in case when we
show overridden bubble it's always 1 account bubble. So these checks are not
true anymore

[vasilii, 2015/08/20 15:11:48]

You are talking about password_overriden case?
It seems like a bad bug that we end up in this bubble then.
PasswordManager::OnLoginSuccessful contains a condition that password_overriden
means "Update". But the password store can be empty.

[dvadym, 2015/08/21 14:09:53]

In case of password_overridden, password store can't be empty, since the user
overrode previously stored password. See description of CL for more details.

-    DCHECK_EQ(parent->model()->local_credentials()[0]->username_value,
-              parent->model()->pending_password().username_value);

[vasilii, 2015/08/19 13:01:18]

If this is untrue then there is a bug in the line # 1091.

Ideally you should summarize everything in a comment here.

[dvadym, 2015/08/20 11:10:11]

Thanks, there was a bug in the line 1091. Fixed.

I've added comment
// |pending_password()| is a form that should be updated, so it should be used
when the user clicks "Update".
I think that the main point which can cause errors here, it's that
pending_password() should be used for Updating (i.e.error in the line #1091), so
I've added this to comment.

[vasilii, 2015/08/20 15:11:48]

I'm concerned about this change. It violates the comment to 
PasswordFormManager::Update. I totally admit that PasswordStore::UpdateLogin may
fail silently.

[dvadym, 2015/08/21 14:09:53]

Strictly speaking using |pending_password| for argument of call of PasswordStore
doesn't violates UpdateLogin, because |pending_password| is one of
|best_matches| in this case
(https://code.google.com/p/chromium/codesearch#chromium/src/components/passwor...).

I agree that this is not obvious. So I'm going to change comment for UpdateLogin
to the following:
...|credentials_to_update| should be one of |best_matches_| or
|pending_credentials|.

I've added comments to PasswordManagerClient::PromptUserToSaveOrUpdatePassword

     std::vector<const autofill::PasswordForm*> forms;
     forms.push_back(&parent->model()->pending_password());
     item = new ManagePasswordItemsView(parent_->model(), forms);
   }
   nope_button_ = new views::LabelButton(
       this, l10n_util::GetStringUTF16(IDS_PASSWORD_MANAGER_CANCEL_BUTTON));
   nope_button_->SetStyle(views::Button::STYLE_BUTTON);
   nope_button_->SetFontList(ui::ResourceBundle::GetSharedInstance().GetFontList(
       ui::ResourceBundle::SmallFont));
 
@@ skipping 44 matching lines @@
   DCHECK(sender == update_button_ || sender == nope_button_);
   if (sender == update_button_) {
     if (selection_view_) {
       // Multi account case.
       parent_->model()->OnUpdateClicked(
           *selection_view_->GetSelectedCredentials());
     } else {
       parent_->model()->OnUpdateClicked(
           *parent_->model()->local_credentials()[0]);
     }
+  } else {
+    parent_->model()->OnNopeUpdateClicked();
   }
   parent_->Close();
 }
 
 void ManagePasswordsBubbleView::UpdatePendingView::StyledLabelLinkClicked(
     const gfx::Range& range,
     int event_flags) {
   DCHECK_EQ(range, parent_->model()->title_brand_link_range());
   parent_->model()->OnBrandLinkClicked();
 }
@@ skipping 139 matching lines @@
 void ManagePasswordsBubbleView::NotifyNeverForThisSiteClicked() {
   if (model()->local_credentials().empty()) {
     // Skip confirmation if there are no existing passwords for this site.
     NotifyConfirmedNeverForThisSite();
   } else {
     model()->OnConfirmationForNeverForThisSite();
     Refresh();
     SizeToContents();
   }
 }