[CCA] Run CameraAppWindowManager as a singleton

To enable CCA on guest mode, CameraAppWindowManager cannot be a
KeyedService since it does not work under guest mode.

Therefore, this CL changes CameraAppWindowManager as a singleton object.

Bug: b/172343942
Test: Manually
Change-Id: Ia4e8970e2e2083af6db58f20d22f00ab17f20b92
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2592184
Commit-Queue: Wei Lee <wtlee@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837043}

chromeos/components/camera_app_ui/BUILD.gn

@@ -16,8 +16,6 @@ static_library("camera_app_ui") {
     "camera_app_ui_delegate.h",
     "camera_app_window_manager.cc",
     "camera_app_window_manager.h",
-    "camera_app_window_manager_factory.cc",
-    "camera_app_window_manager_factory.h",
     "camera_app_window_state_controller.cc",
     "camera_app_window_state_controller.h",
     "resources.h",
@@ -36,8 +34,6 @@ static_library("camera_app_ui") {
     "//chromeos/strings",
     "//chromeos/system",
     "//components/arc",
-    "//components/keyed_service/content",
-    "//components/keyed_service/core",
     "//content/public/browser",
     "//content/public/common",
     "//media/capture:capture_lib",

chromeos/components/camera_app_ui/camera_app_ui.cc

@@ -7,7 +7,6 @@
 #include "ash/public/cpp/window_properties.h"
 #include "base/bind.h"
 #include "chromeos/components/camera_app_ui/camera_app_helper_impl.h"
-#include "chromeos/components/camera_app_ui/camera_app_window_manager_factory.h"
 #include "chromeos/components/camera_app_ui/resources.h"
 #include "chromeos/components/camera_app_ui/url_constants.h"
 #include "components/arc/intent_helper/arc_intent_helper_bridge.h"
@@ -251,8 +250,7 @@ aura::Window* CameraAppUI::window() {
 }
 
 CameraAppWindowManager* CameraAppUI::app_window_manager() {
-  return chromeos::CameraAppWindowManagerFactory::GetForBrowserContext(
-      web_ui()->GetWebContents()->GetBrowserContext());
+  return chromeos::CameraAppWindowManager::GetInstance();
 }
 
 const GURL& CameraAppUI::url() {

chromeos/components/camera_app_ui/camera_app_window_manager.cc

@@ -6,20 +6,26 @@
 
 #include "chromeos/components/camera_app_ui/camera_app_helper_impl.h"
 #include "chromeos/components/camera_app_ui/url_constants.h"
+#include "content/public/browser/browser_thread.h"
 #include "ui/aura/window.h"
 #include "ui/views/widget/widget.h"
 
 namespace chromeos {
 
-CameraAppWindowManager::CameraAppWindowManager() = default;
-
 CameraAppWindowManager::~CameraAppWindowManager() = default;
 
+// static
+CameraAppWindowManager* CameraAppWindowManager::GetInstance() {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  return base::Singleton<CameraAppWindowManager>::get();
+}
+
 void CameraAppWindowManager::SetCameraUsageMonitor(
     aura::Window* window,
     mojo::PendingRemote<chromeos_camera::mojom::CameraUsageOwnershipMonitor>
         usage_monitor,
     base::OnceCallback<void()> callback) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   auto* widget = views::Widget::GetWidgetForNativeWindow(window);
 
   mojo::Remote<chromeos_camera::mojom::CameraUsageOwnershipMonitor> remote(
@@ -39,6 +45,7 @@ void CameraAppWindowManager::SetCameraUsageMonitor(
 
 void CameraAppWindowManager::OnWidgetVisibilityChanged(views::Widget* widget,
                                                        bool visible) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   // This event will be triggered and the |visible| will be set to:
   // * True:
   //     1. When the window is restored from minimized.
@@ -75,6 +82,7 @@ void CameraAppWindowManager::OnWidgetVisibilityChanged(views::Widget* widget,
 
 void CameraAppWindowManager::OnWidgetActivationChanged(views::Widget* widget,
                                                        bool active) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   // This event will be triggered and the |active| will be set to:
   // * True:
   //     1. When the window is restored from minimized.
@@ -113,9 +121,12 @@ void CameraAppWindowManager::OnWidgetActivationChanged(views::Widget* widget,
 }
 
 void CameraAppWindowManager::OnWidgetDestroying(views::Widget* widget) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   widget->RemoveObserver(this);
 }
 
+CameraAppWindowManager::CameraAppWindowManager() = default;
+
 void CameraAppWindowManager::OnMonitorMojoConnectionError(
     views::Widget* widget) {
   camera_usage_monitors_.erase(widget);
@@ -192,6 +203,4 @@ void CameraAppWindowManager::ResumeNextOrIdle() {
   }
 }
 
-void CameraAppWindowManager::Shutdown() {}
-
 }  // namespace chromeos

chromeos/components/camera_app_ui/camera_app_window_manager.h

@@ -6,8 +6,8 @@
 #define CHROMEOS_COMPONENTS_CAMERA_APP_UI_CAMERA_APP_WINDOW_MANAGER_H_
 
 #include "base/containers/flat_map.h"
+#include "base/memory/singleton.h"
 #include "chromeos/components/camera_app_ui/camera_app_helper.mojom.h"
-#include "components/keyed_service/core/keyed_service.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "ui/views/widget/widget_observer.h"
 
@@ -22,16 +22,16 @@ class Widget;
 namespace chromeos {
 
 // A manager to manage the camera usage ownership between multiple camera app
-// windows. The windows share the same window manager if they are under same
-// browser context.
-class CameraAppWindowManager : public KeyedService,
-                               public views::WidgetObserver {
+// windows. The clients should only use this object as a singleton instance and
+// should only access it on the UI thread.
+class CameraAppWindowManager : public views::WidgetObserver {
  public:
-  CameraAppWindowManager();
   CameraAppWindowManager(const CameraAppWindowManager&) = delete;
   CameraAppWindowManager& operator=(const CameraAppWindowManager&) = delete;
   ~CameraAppWindowManager() override;
 
+  static CameraAppWindowManager* GetInstance();
+
   void SetCameraUsageMonitor(
       aura::Window* window,
       mojo::PendingRemote<chromeos_camera::mojom::CameraUsageOwnershipMonitor>
@@ -44,6 +44,9 @@ class CameraAppWindowManager : public KeyedService,
   void OnWidgetDestroying(views::Widget* widget) override;
 
  private:
+  CameraAppWindowManager();
+
+  friend struct base::DefaultSingletonTraits<CameraAppWindowManager>;
   enum class TransferState {
     kIdle,
     kSuspending,
@@ -56,9 +59,6 @@ class CameraAppWindowManager : public KeyedService,
   void OnResumedCameraUsage(views::Widget* prev_owner);
   void ResumeNextOrIdle();
 
-  // KeyedService:
-  void Shutdown() override;
-
   base::flat_map<
       views::Widget*,
       mojo::Remote<chromeos_camera::mojom::CameraUsageOwnershipMonitor>>

chromeos/components/camera_app_ui/camera_app_window_manager_factory.cc

-// Copyright 2020 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 "chromeos/components/camera_app_ui/camera_app_window_manager_factory.h"
-
-#include "base/macros.h"
-#include "chromeos/components/camera_app_ui/camera_app_window_manager.h"
-#include "components/keyed_service/content/browser_context_dependency_manager.h"
-#include "components/keyed_service/core/keyed_service.h"
-#include "content/public/browser/browser_context.h"
-
-namespace chromeos {
-
-// static
-CameraAppWindowManager* CameraAppWindowManagerFactory::GetForBrowserContext(
-    content::BrowserContext* browser_context) {
-  return static_cast<CameraAppWindowManager*>(
-      GetInstance()->GetServiceForBrowserContext(browser_context, true));
-}
-
-// static
-CameraAppWindowManagerFactory* CameraAppWindowManagerFactory::GetInstance() {
-  return base::Singleton<CameraAppWindowManagerFactory>::get();
-}
-
-CameraAppWindowManagerFactory::CameraAppWindowManagerFactory()
-    : BrowserContextKeyedServiceFactory(
-          "CameraAppWindowManagerFactory",
-          BrowserContextDependencyManager::GetInstance()) {}
-
-CameraAppWindowManagerFactory::~CameraAppWindowManagerFactory() {}
-
-KeyedService* CameraAppWindowManagerFactory::BuildServiceInstanceFor(
-    content::BrowserContext* context) const {
-  return new CameraAppWindowManager();
-}
-
-}  // namespace chromeos

chromeos/components/camera_app_ui/camera_app_window_manager_factory.h

-// Copyright 2020 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 CHROMEOS_COMPONENTS_CAMERA_APP_UI_CAMERA_APP_WINDOW_MANAGER_FACTORY_H_
-#define CHROMEOS_COMPONENTS_CAMERA_APP_UI_CAMERA_APP_WINDOW_MANAGER_FACTORY_H_
-
-#include "base/memory/singleton.h"
-#include "chromeos/components/camera_app_ui/camera_app_window_manager.h"
-#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
-
-class KeyedService;
-
-namespace content {
-class BrowserContext;
-}  // namespace content
-
-namespace chromeos {
-
-// Owns CameraAppWindowManager instances and associates them with Profiles. Note
-// that the window manager can also work for app instance even if it is launched
-// by typing URL under incognito mode.
-class CameraAppWindowManagerFactory : public BrowserContextKeyedServiceFactory {
- public:
-  static CameraAppWindowManager* GetForBrowserContext(
-      content::BrowserContext* context);
-
-  static CameraAppWindowManagerFactory* GetInstance();
-
- private:
-  friend struct base::DefaultSingletonTraits<CameraAppWindowManagerFactory>;
-
-  CameraAppWindowManagerFactory();
-  ~CameraAppWindowManagerFactory() override;
-
-  // BrowserContextKeyedServiceFactory:
-  KeyedService* BuildServiceInstanceFor(
-      content::BrowserContext* context) const override;
-
-  DISALLOW_COPY_AND_ASSIGN(CameraAppWindowManagerFactory);
-};
-
-}  // namespace chromeos
-
-#endif  // CHROMEOS_COMPONENTS_CAMERA_APP_UI_CAMERA_APP_WINDOW_MANAGER_FACTORY_H_