Extract colors from wallpaper and dynamically update login screen overlay

chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_LOGIN_USERS_WALLPAPER_WALLPAPER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USERS_WALLPAPER_WALLPAPER_MANAGER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "ash/public/interfaces/wallpaper.mojom.h"
+#include "ash/shelf/shelf_constants.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
 #include "chrome/browser/chromeos/customization/customization_wallpaper_downloader.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "components/user_manager/user.h"
 #include "components/user_manager/user_image/user_image.h"
 #include "components/user_manager/user_manager.h"
+#include "components/wallpaper/wallpaper_color_calculator.h"
+#include "components/wallpaper/wallpaper_color_calculator_observer.h"
 #include "components/wallpaper/wallpaper_layout.h"
 #include "components/wallpaper/wallpaper_manager_base.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "ui/aura/window_observer.h"
+#include "ui/gfx/color_utils.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/wm/public/activation_change_observer.h"
 #include "ui/wm/public/activation_client.h"
 
 namespace chromeos {
 
 class WallpaperManager
     : public wallpaper::WallpaperManagerBase,
       public ash::mojom::WallpaperPicker,
       public content::NotificationObserver,
@@ skipping 68 matching lines @@
   void UserChangedChildStatus(user_manager::User* user) override;
 
   // wm::ActivationChangeObserver:
   void OnWindowActivated(ActivationReason reason,
                          aura::Window* gained_active,
                          aura::Window* lost_active) override;
 
   // aura::WindowObserver:
   void OnWindowDestroying(aura::Window* window) override;
 
+  // Setting a non-NULL observer indicates that color calculation is needed

[jdufault, 2017/06/10 03:05:59]

nit: non-null

[Wenzhao (Colin) Zang, 2017/06/12 21:10:58]

Done.

+  // when a wallpaper is set.

[jdufault, 2017/06/10 03:05:59]

Generally, try to avoid encoding state information in a null/non-null value. Use
base::Optional for that instead, as it conveys more semantic meaning.

[Wenzhao (Colin) Zang, 2017/06/12 21:10:58]

Done.

+  void SetLoginOverlayCalculatorObserver(

[jdufault, 2017/06/10 03:05:59]

These functions should go above the overrides (overrides go last).

[jdufault, 2017/06/10 03:05:59]

This should follow the standard AddObserver/RemoveObserver pattern. See
base::ObserverList. Register SigninScreenHandler as an observer on construction,
and deregister in SigninScreenHandler dtor.

[Wenzhao (Colin) Zang, 2017/06/12 21:10:58]

Done.

[Wenzhao (Colin) Zang, 2017/06/12 21:10:58]

Done.

+      wallpaper::WallpaperColorCalculatorObserver*);

[jdufault, 2017/06/10 03:05:59]

Set a variable name here.

[Wenzhao (Colin) Zang, 2017/06/12 21:10:58]

Done.

+
+  // Must be called after color calculation succeeds. Get the actual colors
+  // which will be used in login screen based on the prominent color.
+  void getLoginOverlayColors(std::string* dm_color,

[jdufault, 2017/06/10 03:05:59]

nit: Out parameters should have out_ prefix.

[jdufault, 2017/06/10 03:05:59]

nit: get -> Get

[Wenzhao (Colin) Zang, 2017/06/12 21:10:57]

Done.

[Wenzhao (Colin) Zang, 2017/06/12 21:10:57]

Done.

+                             std::string* scroll_color,
+                             std::string* background_color);
+
  private:
   friend class TestApi;
   friend class WallpaperManagerBrowserTest;
   friend class WallpaperManagerBrowserTestDefaultWallpaper;
   friend class WallpaperManagerPolicyTest;
 
   WallpaperManager();
 
   // Returns modifiable PendingWallpaper.
   // Returns pending_inactive_ or creates new PendingWallpaper if necessary.
@@ skipping 26 matching lines @@
   // device wallpaper policy setting.
   void OnCheckDeviceWallpaperMatchHash(const AccountId& account_id,
                                        const std::string& url,
                                        const std::string& hash,
                                        bool match);
   // This is called when the device wallpaper is decoded successfully.
   void OnDeviceWallpaperDecoded(
       const AccountId& account_id,
       std::unique_ptr<user_manager::UserImage> user_image);
 
+  // If the calculator observer is not NULL, calculate a prominent color based

[jdufault, 2017/06/10 03:05:59]

nit: NULL -> null

[Wenzhao (Colin) Zang, 2017/06/12 21:10:58]

Done.

+  // on the wallpaper image. An existing calculation in progress (if any) will
+  // be destroyed first.
+  void CalculateProminentColor(const gfx::ImageSkia& image);
+
   // wallpaper::WallpaperManagerBase:
   void InitializeRegisteredDeviceWallpaper() override;
   bool GetUserWallpaperInfo(const AccountId& account_id,
                             wallpaper::WallpaperInfo* info) const override;
   // Returns true if the device wallpaper should be set for the account.
   bool ShouldSetDeviceWallpaper(const AccountId& account_id,
                                 std::string* url,
                                 std::string* hash) override;
   base::FilePath GetDeviceWallpaperDir() override;
   base::FilePath GetDeviceWallpaperFilePath() override;
@@ skipping 61 matching lines @@
   PendingList loading_;
 
   content::NotificationRegistrar registrar_;
 
   ScopedObserver<wm::ActivationClient, wm::ActivationChangeObserver>
       activation_client_observer_;
   ScopedObserver<aura::Window, aura::WindowObserver> window_observer_;
 
   base::WeakPtrFactory<WallpaperManager> weak_factory_;
 
+  std::unique_ptr<wallpaper::WallpaperColorCalculator> color_calculator_;
+
+  wallpaper::WallpaperColorCalculatorObserver*
+      login_overlay_calculator_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(WallpaperManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USERS_WALLPAPER_WALLPAPER_MANAGER_H_