[Cros-SR Logging] Adds GetClient to AppListController interface

Adds GetClient() method to AppListController interface that enables
us to notify Chrome from Ash side.
E.g. AppListController::Get()->GetClient()->SomeAction()

Bug: 972817
Change-Id: I3205848e152943295f070c1dfec499b85f3616b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1659664
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Jia Meng <jiameng@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#669556}

ash/app_list/app_list_controller_impl.cc

@@ -176,6 +176,11 @@ void AppListControllerImpl::SetClient(app_list::AppListClient* client) {
   client_ = client;
 }
 
+app_list::AppListClient* AppListControllerImpl::GetClient() {
+  DCHECK(client_);
+  return client_;
+}
+
 app_list::AppListModel* AppListControllerImpl::GetModel() {
   return model_.get();
 }

ash/app_list/app_list_controller_impl.h

@@ -75,6 +75,7 @@ class ASH_EXPORT AppListControllerImpl
 
   // app_list::AppListController:
   void SetClient(app_list::AppListClient* client) override;
+  app_list::AppListClient* GetClient() override;
   void AddItem(std::unique_ptr<ash::AppListItemMetadata> app_item) override;
   void AddItemToFolder(std::unique_ptr<ash::AppListItemMetadata> app_item,
                        const std::string& folder_id) override;

ash/public/cpp/app_list/app_list_controller.h

@@ -33,6 +33,9 @@ class ASH_PUBLIC_EXPORT AppListController {
   // Sets a client to handle calls from Ash.
   virtual void SetClient(AppListClient* client) = 0;
 
+  // Gets the client that handles calls from Ash.
+  virtual AppListClient* GetClient() = 0;
+
   // Adds an item to AppListModel.
   virtual void AddItem(std::unique_ptr<ash::AppListItemMetadata> app_item) = 0;