desktop-pwas: Make FileHandlerManager observe AppRegistrar.

This is the first step in registering Windows file associations
for web apps, when a web app is installed whose manifest specifies
that it can handle specific file extensions.

Bug: 960245
Change-Id: I8a2c8932cb69af5caf7c79f11f7881fad0687b3f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1788117Reviewed-by: Alexey Baskakov <loyso@chromium.org>
Commit-Queue: David Bienvenu <davidbienvenu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695123}

chrome/browser/web_applications/components/BUILD.gn

@@ -13,6 +13,7 @@ source_set("components") {
     "external_install_options.h",
     "externally_installed_web_app_prefs.cc",
     "externally_installed_web_app_prefs.h",
+    "file_handler_manager.cc",
     "file_handler_manager.h",
     "install_bounce_metric.cc",
     "install_bounce_metric.h",

chrome/browser/web_applications/components/file_handler_manager.cc

+// Copyright 2019 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 "chrome/browser/web_applications/components/file_handler_manager.h"
+
+namespace web_app {
+
+FileHandlerManager::FileHandlerManager(Profile* profile)
+    : profile_(profile), registrar_observer_(this) {}
+
+FileHandlerManager::~FileHandlerManager() = default;
+
+void FileHandlerManager::SetSubsystems(AppRegistrar* registrar) {
+  registrar_ = registrar;
+  registrar_observer_.Add(registrar);
+}
+
+void FileHandlerManager::OnWebAppInstalled(const AppId& installed_app_id) {
+  // TODO(davidbienvenu): Hook up with file association registration code on
+  // windows.
+}
+
+void FileHandlerManager::OnWebAppUninstalled(const AppId& installed_app_id) {
+  // TODO(davidbienvenu): Hook up to file association de-registration code on
+  // windows.
+}
+
+void FileHandlerManager::OnAppRegistrarDestroyed() {
+  registrar_observer_.RemoveAll();
+}
+
+}  // namespace web_app

chrome/browser/web_applications/components/file_handler_manager.h

@@ -8,6 +8,9 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/scoped_observer.h"
+#include "chrome/browser/web_applications/components/app_registrar.h"
+#include "chrome/browser/web_applications/components/app_registrar_observer.h"
 #include "chrome/browser/web_applications/components/web_app_helpers.h"
 #include "components/services/app_service/public/cpp/file_handler_info.h"
 
@@ -15,10 +18,13 @@ class Profile;
 
 namespace web_app {
 
-class FileHandlerManager {
+class FileHandlerManager : public AppRegistrarObserver {
  public:
-  explicit FileHandlerManager(Profile* profile) : profile_(profile) {}
-  virtual ~FileHandlerManager() = default;
+  explicit FileHandlerManager(Profile* profile);
+  ~FileHandlerManager() override;
+
+  // |registrar| is used to observe OnWebAppInstalled/Uninstalled events.
+  void SetSubsystems(AppRegistrar* registrar);
 
   // Gets all file handlers for |app_id|. |nullptr| if the app has no file
   // handlers.
@@ -31,6 +37,14 @@ class FileHandlerManager {
 
  private:
   Profile* const profile_;
+  AppRegistrar* registrar_ = nullptr;
+
+  // AppRegistrarObserver:
+  void OnWebAppInstalled(const AppId& app_id) override;
+  void OnWebAppUninstalled(const AppId& app_id) override;
+  void OnAppRegistrarDestroyed() override;
+
+  ScopedObserver<AppRegistrar, AppRegistrarObserver> registrar_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(FileHandlerManager);
 };

chrome/browser/web_applications/web_app_provider.cc

@@ -190,6 +190,7 @@ void WebAppProvider::ConnectSubsystems() {
   system_web_app_manager_->SetSubsystems(pending_app_manager_.get(),
                                          registrar_.get(), ui_manager_.get());
   web_app_policy_manager_->SetSubsystems(pending_app_manager_.get());
+  file_handler_manager_->SetSubsystems(registrar_.get());
 
   connected_ = true;
 }