Extract colors from wallpaper and dynamically update login screen overlay

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

 // Copyright (c) 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 
 #include "ash/public/interfaces/touch_view.mojom.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
 #include "chrome/browser/chromeos/lock_screen_apps/state_observer.h"
 #include "chrome/browser/chromeos/login/screens/error_screen.h"
 #include "chrome/browser/chromeos/login/signin_specifics.h"
 #include "chrome/browser/chromeos/login/ui/login_display.h"
+#include "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/ui/webui/chromeos/login/base_webui_handler.h"
 #include "chrome/browser/ui/webui/chromeos/login/network_state_informer.h"
 #include "chrome/browser/ui/webui/chromeos/login/oobe_ui.h"
 #include "chromeos/dbus/power_manager_client.h"
 #include "chromeos/network/portal_detector/network_portal_detector.h"
 #include "components/proximity_auth/screenlock_bridge.h"
 #include "components/user_manager/user_manager.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ skipping 197 matching lines @@
 // LoginDisplay.
 class SigninScreenHandler
     : public BaseWebUIHandler,
       public LoginDisplayWebUIHandler,
       public content::NotificationObserver,
       public NetworkStateInformer::NetworkStateInformerObserver,
       public PowerManagerClient::Observer,
       public input_method::ImeKeyboard::Observer,
       public ash::mojom::TouchViewObserver,
       public lock_screen_apps::StateObserver,
-      public OobeUI::Observer {
+      public OobeUI::Observer,
+      public WallpaperManager::Observer {

[xdai1, 2017/06/13 23:04:24]

WallpaperManagerBase::Observer?

[Wenzhao (Colin) Zang, 2017/06/14 00:44:50]

It's changed. Thanks. For some reason other classes use
WallpaperManager::Observer though, e.g.
https://cs.chromium.org/chromium/src/chrome/browser/chromeos/login/users/wall...

  public:
   SigninScreenHandler(
       const scoped_refptr<NetworkStateInformer>& network_state_informer,
       ErrorScreen* error_screen,
       CoreOobeView* core_oobe_view,
       GaiaScreenHandler* gaia_screen_handler,
       JSCallsContainer* js_calls_container);
   ~SigninScreenHandler() override;
 
   static std::string GetUserLastInputMethod(const std::string& username);
@@ skipping 17 matching lines @@
   void OnNetworkReady() override;
   void UpdateState(NetworkError::ErrorReason reason) override;
 
   // Required Local State preferences.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
   // OobeUI::Observer implemetation.
   void OnCurrentScreenChanged(OobeScreen current_screen,
                               OobeScreen new_screen) override;
 
+  // WallpaperManager::Observer implementation.
+  void OnColorCalculationComplete() override;
+
+  // WallpaperManager::Observer implementation.
+  void OnWallpaperAnimationFinished(const AccountId& account_id) override;

[xdai1, 2017/06/13 23:04:24]

Any reason it was made a pure virtual function in
WallpaperManagerBase::Observer? Can we make it not pure virtual function? 

[Wenzhao (Colin) Zang, 2017/06/14 00:44:50]

I'm also wondering. I see all other subclasses have an empty implementation as
well. I just feel changing that is beyond the scope of this CL. 

[xdai1, 2017/06/14 18:23:40]

Acknowledged. Could you address this in a separate CL?

Btw: you don't need "// wallpaper::WallpaperManagerBase::Observer
implementation." twice. Remove the one in line 285 and remove the blank line in
284.

[Wenzhao (Colin) Zang, 2017/06/15 18:14:40]

Done.

+
   void SetFocusPODCallbackForTesting(base::Closure callback);
 
   // To avoid spurious error messages on flaky networks, the offline message is
   // only shown if the network is offline for a threshold number of seconds.
   // This method reduces the threshold to zero, allowing the offline message to
   // show instantaneously in tests.
   void ZeroOfflineTimeoutForTesting();
 
   // Gets the keyboard remapped pref value for |pref_name| key. Returns true if
   // successful, otherwise returns false.
@@ skipping 17 matching lines @@
   // |params| argument.
   void UpdateUIState(UIState ui_state, base::DictionaryValue* params);
 
   void UpdateStateInternal(NetworkError::ErrorReason reason, bool force_update);
   void SetupAndShowOfflineMessage(NetworkStateInformer::State state,
                                   NetworkError::ErrorReason reason);
   void HideOfflineMessage(NetworkStateInformer::State state,
                           NetworkError::ErrorReason reason);
   void ReloadGaia(bool force_reload);
 
+  // Sets signin screen overlay colors based on the wallpaper color extraction
+  // results.
+  void SetSigninScreenColors(SkColor dm_color);
+
   // BaseScreenHandler implementation:
   void DeclareLocalizedValues(
       ::login::LocalizedValuesBuilder* builder) override;
   void Initialize() override;
   gfx::NativeWindow GetNativeWindow() override;
 
   // WebUIMessageHandler implementation:
   void RegisterMessages() override;
 
   // LoginDisplayWebUIHandler implementation:
@@ skipping 231 matching lines @@
       lock_screen_apps_observer_;
 
   base::WeakPtrFactory<SigninScreenHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_