Move all login screen related constants to a separate file

Login/lock screen related constants may be used from at least three
places: views-based lock, WebUi based login/lock and wallpaper. So
we want to move them together just as shelf_constants.h

Bug: 732566, 733409
Change-Id: I791d5dfbd02f35cdcc6064b964b97b6978a376d2
Reviewed-on: https://chromium-review.googlesource.com/590483Reviewed-by: Dan Erat <derat@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491196}

ash/BUILD.gn

@@ -217,6 +217,7 @@ component("ash") {
     "login/ui/lock_window.h",
     "login/ui/login_auth_user_view.cc",
     "login/ui/login_auth_user_view.h",
+    "login/ui/login_constants.h",
     "login/ui/login_data_dispatcher.cc",
     "login/ui/login_data_dispatcher.h",
     "login/ui/login_password_view.cc",

ash/login/ui/lock_screen.cc

@@ -7,6 +7,7 @@
 #include "ash/login/ui/lock_contents_view.h"
 #include "ash/login/ui/lock_debug_view.h"
 #include "ash/login/ui/lock_window.h"
+#include "ash/login/ui/login_constants.h"
 #include "ash/login/ui/login_data_dispatcher.h"
 #include "ash/public/interfaces/session_controller.mojom.h"
 #include "ash/root_window_controller.h"
@@ -99,15 +100,12 @@ void LockScreen::Destroy() {
 }
 
 void LockScreen::ToggleBlur() {
-  // TODO(jdufault): Use correct blur amount.
-  float target_blur = 20.0f;
-
   for (aura::Window* window : Shell::GetAllRootWindows()) {
     ui::Layer* layer = GetWallpaperLayerForWindow(window);
-    if (layer->layer_blur() == target_blur) {
+    if (layer->layer_blur() > 0.0f) {
       layer->SetLayerBlur(0.0f);
     } else {
-      layer->SetLayerBlur(target_blur);
+      layer->SetLayerBlur(login_constants::kBlurSigma);
     }
   }
 }

ash/login/ui/login_constants.h

+// Copyright 2017 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.
+
+#ifndef ASH_LOGIN_UI_LOGIN_CONSTANTS_H
+#define ASH_LOGIN_UI_LOGIN_CONSTANTS_H
+
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace ash {
+namespace login_constants {
+
+// The default base color of the login/lock screen when the dark muted color
+// extracted from wallpaper is invalid.
+constexpr SkColor kDefaultBaseColor = SK_ColorBLACK;
+
+// The alpha value for the login/lock screen background.
+constexpr int kTranslucentAlpha = 153;
+
+// The alpha value for the scrollable container on the account picker.
+constexpr int kScrollTranslucentAlpha = 76;
+
+// The alpha value used to darken the login/lock screen.
+constexpr int kTranslucentColorDarkenAlpha = 128;
+
+// The blur sigma for login/lock screen.
+constexpr float kBlurSigma = 30.0f;
+
+}  // namespace login_constants
+}  // namespace ash
+
+#endif  // ASH_LOGIN_UI_LOGIN_CONSTANTS_H
\ No newline at end of file

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

@@ -9,9 +9,9 @@
 #include <algorithm>
 #include <vector>
 
+#include "ash/login/ui/login_constants.h"
 #include "ash/public/interfaces/constants.mojom.h"
 #include "ash/public/interfaces/tray_action.mojom.h"
-#include "ash/shelf/shelf_constants.h"
 #include "ash/shell.h"
 #include "ash/shutdown_reason.h"
 #include "ash/system/devicetype_utils.h"
@@ -132,11 +132,6 @@ const char kAvailableLockScreenApps[] = "LOCK_SCREEN_APPS_STATE.AVAILABLE";
 const char kLaunchRequestedLockScreenApps[] =
     "LOCK_SCREEN_APPS_STATE.LAUNCH_REQUESTED";
 
-// The alpha value for the signin screen background.
-// TODO(crbug.com/732566): Move all constants related to views-based signin
-// screen to a separate file.
-constexpr int kLoginTranslucentAlpha = 76;
-
 class CallOnReturn {
  public:
   explicit CallOnReturn(const base::Closure& callback)
@@ -874,12 +869,13 @@ void SigninScreenHandler::SetSigninScreenColors(SkColor dark_muted_color) {
   // The dark muted color should have 100% opacity.
   dark_muted_color = SkColorSetA(dark_muted_color, 0xFF);
   SkColor base_color = color_utils::GetResultingPaintColor(
-      SkColorSetA(ash::kShelfDefaultBaseColor,
-                  ash::kShelfTranslucentColorDarkenAlpha),
+      SkColorSetA(ash::login_constants::kDefaultBaseColor,
+                  ash::login_constants::kTranslucentColorDarkenAlpha),
       dark_muted_color);
   SkColor background_color =
-      SkColorSetA(base_color, ash::kShelfTranslucentAlpha);
-  SkColor scroll_color = SkColorSetA(base_color, kLoginTranslucentAlpha);
+      SkColorSetA(base_color, ash::login_constants::kTranslucentAlpha);
+  SkColor scroll_color =
+      SkColorSetA(base_color, ash::login_constants::kScrollTranslucentAlpha);
   CallJS("login.AccountPickerScreen.setOverlayColors",
          color_utils::SkColorToRgbaString(dark_muted_color),
          color_utils::SkColorToRgbaString(scroll_color),