Revert "cros: Views login/lock clear password when switching active auth user."

This reverts commit 86a87223.

Reason for revert:
ash_unittests LoginAuthUserViewUnittest.PasswordClearedAfterAnimationIfPasswordDisabled
has been failing on linux-chromeos-dbg since this landed in
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/linux-chromeos-dbg/6443

Original change's description:
> cros: Views login/lock clear password when switching active auth user.
> 
> Bug: 855725
> Change-Id: I91f6bab46701c9d66bc8b497661c460a7968619f
> Reviewed-on: https://chromium-review.googlesource.com/1112075
> Commit-Queue: Jacob Dufault <jdufault@chromium.org>
> Reviewed-by: Xiaoyin Hu <xiaoyinh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#569802}

TBR=jdufault@chromium.org,xiaoyinh@chromium.org

Change-Id: I7a54ed3ba91ea6a9adb46f83852488ed1c76178c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 855725
Reviewed-on: https://chromium-review.googlesource.com/1112980Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569882}

ash/login/ui/login_auth_user_view.cc

@@ -101,26 +101,6 @@ ui::CallbackLayerAnimationObserver* BuildObserverToHideView(views::View* view) {
       view));
 }
 
-// Clears the password for the given |LoginPasswordView| instance and then
-// deletes itself.
-class ClearPasswordAnimationObserver : public ui::ImplicitAnimationObserver {
- public:
-  explicit ClearPasswordAnimationObserver(LoginPasswordView* view)
-      : view_(view) {}
-  ~ClearPasswordAnimationObserver() override = default;
-
-  // ui::ImplicitAnimationObserver:
-  void OnImplicitAnimationsCompleted() override {
-    view_->Clear();
-    delete this;
-  }
-
- private:
-  LoginPasswordView* view_;
-
-  DISALLOW_COPY_AND_ASSIGN(ClearPasswordAnimationObserver);
-};
-
 // A view which has a round border and a fingerprint icon at the center.
 class FingerprintIconView : public views::View {
  public:
@@ -568,10 +548,6 @@ void LoginAuthUserView::ApplyAnimationPostLayout() {
       settings.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
           login_constants::kChangeUserAnimationDurationMs));
       settings.SetTweenType(gfx::Tween::Type::FAST_OUT_SLOW_IN);
-      if (cached_animation_state_->had_password && !has_password) {
-        settings.AddObserver(
-            new ClearPasswordAnimationObserver(password_view_));
-      }
 
       password_view_->layer()->SetOpacity(opacity_end);
     }

ash/login/ui/login_auth_user_view_unittest.cc

@@ -12,7 +12,6 @@
 #include "ash/strings/grit/ash_strings.h"
 #include "base/bind_helpers.h"
 #include "base/run_loop.h"
-#include "base/strings/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/events/event_utils.h"
@@ -164,32 +163,4 @@ TEST_F(LoginAuthUserViewUnittest, OnlineSignInMessage) {
   EXPECT_FALSE(online_sign_in_message->visible());
 }
 
-// Verifies that password is cleared after AUTH_PASSWORD is disabled.
-TEST_F(LoginAuthUserViewUnittest,
-       PasswordClearedAfterAnimationIfPasswordDisabled) {
-  LoginPasswordView::TestApi password_test(view_->password_view());
-  auto has_password = [&]() {
-    return !password_test.textfield()->text().empty();
-  };
-
-  // Set a password.
-  view_->SetAuthMethods(LoginAuthUserView::AUTH_PASSWORD);
-  password_test.textfield()->SetText(base::ASCIIToUTF16("Hello"));
-
-  // Enable some other auth method (PIN), password is not cleared.
-  view_->CaptureStateForAnimationPreLayout();
-  view_->SetAuthMethods(LoginAuthUserView::AUTH_PASSWORD |
-                        LoginAuthUserView::AUTH_PIN);
-  EXPECT_TRUE(has_password());
-  view_->ApplyAnimationPostLayout();
-  EXPECT_TRUE(has_password());
-
-  // Disable password, password is cleared.
-  view_->CaptureStateForAnimationPreLayout();
-  view_->SetAuthMethods(LoginAuthUserView::AUTH_NONE);
-  EXPECT_TRUE(has_password());
-  view_->ApplyAnimationPostLayout();
-  EXPECT_FALSE(has_password());
-}
-
 }  // namespace ash