lacros: Add GetDisplayedNotifications to MessageCenter crosapi

This method returns a list of the ids of displayed notifications. Later
CLs will use this for two things:

- To re-synchronize lacros-chrome's cached view of existing
  notifications after a crash (see C++ NotificationPlatformBridge
  GetDisplayed() method).
- To integration-test the MessageCenter crosapi.

Bug: 1134389
Test: added to unit_tests
Change-Id: Iad877a20216c813b72c265d1b23deb1cfeed1353
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2445849Reviewed-by: Jun Mukai <mukai@chromium.org>
Reviewed-by: Erik Chen <erikchen@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813243}

chrome/browser/chromeos/crosapi/message_center_ash.cc

@@ -4,7 +4,9 @@
 
 #include "chrome/browser/chromeos/crosapi/message_center_ash.h"
 
+#include <string>
 #include <utility>
+#include <vector>
 
 #include "base/bind.h"
 #include "base/check.h"
@@ -177,4 +179,14 @@ void MessageCenterAsh::CloseNotification(const std::string& id) {
   mc::MessageCenter::Get()->RemoveNotification(id, /*by_user=*/false);
 }
 
+void MessageCenterAsh::GetDisplayedNotifications(
+    GetDisplayedNotificationsCallback callback) {
+  mc::NotificationList::Notifications notifications =
+      mc::MessageCenter::Get()->GetNotifications();
+  std::vector<std::string> ids;
+  for (mc::Notification* notification : notifications)
+    ids.push_back(notification->id());
+  std::move(callback).Run(ids);
+}
+
 }  // namespace crosapi

chrome/browser/chromeos/crosapi/message_center_ash.h

@@ -27,6 +27,8 @@ class MessageCenterAsh : public mojom::MessageCenter {
       mojom::NotificationPtr notification,
       mojo::PendingRemote<mojom::NotificationDelegate> delegate) override;
   void CloseNotification(const std::string& id) override;
+  void GetDisplayedNotifications(
+      GetDisplayedNotificationsCallback callback) override;
 
  private:
   mojo::Receiver<mojom::MessageCenter> receiver_;

chrome/browser/chromeos/crosapi/message_center_ash_unittest.cc

@@ -4,21 +4,28 @@
 
 #include "chrome/browser/chromeos/crosapi/message_center_ash.h"
 
+#include <memory>
+#include <string>
+
 #include "base/optional.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/task_environment.h"
 #include "base/time/time.h"
+#include "chromeos/crosapi/mojom/message_center.mojom-test-utils.h"
 #include "chromeos/crosapi/mojom/message_center.mojom.h"
 #include "chromeos/crosapi/mojom/notification.mojom.h"
 #include "mojo/public/cpp/bindings/remote.h"
+#include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_unittest_util.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/public/cpp/notification.h"
 #include "ui/message_center/public/cpp/notification_delegate.h"
+#include "ui/message_center/public/cpp/notifier_id.h"
 #include "url/gurl.h"
 
 using base::ASCIIToUTF16;
@@ -28,6 +35,16 @@ using gfx::test::AreImagesEqual;
 namespace crosapi {
 namespace {
 
+// Creates an ash message center notification.
+std::unique_ptr<message_center::Notification> CreateNotificationWithId(
+    const std::string& id) {
+  return std::make_unique<message_center::Notification>(
+      message_center::NOTIFICATION_TYPE_SIMPLE, id, ASCIIToUTF16("title"),
+      ASCIIToUTF16("message"), /*icon=*/gfx::Image(),
+      /*display_source=*/base::string16(), GURL(), message_center::NotifierId(),
+      message_center::RichNotificationData(), /*delegate=*/nullptr);
+}
+
 class MojoDelegate : public mojom::NotificationDelegate {
  public:
   MojoDelegate() = default;
@@ -325,5 +342,20 @@ TEST_F(MessageCenterAshTest, UserActions) {
   EXPECT_EQ(1, mojo_delegate.closed_count_);
 }
 
+TEST_F(MessageCenterAshTest, GetDisplayedNotifications) {
+  // Create an ash-side notification.
+  auto* message_center = message_center::MessageCenter::Get();
+  message_center->AddNotification(CreateNotificationWithId("id0"));
+  message_center->AddNotification(CreateNotificationWithId("id1"));
+
+  // Get the list of notifications.
+  mojom::MessageCenterAsyncWaiter waiter(message_center_remote_.get());
+  std::vector<std::string> ids;
+  waiter.GetDisplayedNotifications(&ids);
+
+  // The notifications ids are returned. No particular order is specified.
+  EXPECT_THAT(ids, testing::UnorderedElementsAre("id0", "id1"));
+}
+
 }  // namespace
 }  // namespace crosapi

chrome/browser/notifications/notification_platform_bridge_lacros_unittest.cc

@@ -95,6 +95,9 @@ class TestMessageCenter : public crosapi::mojom::MessageCenter {
     last_close_id_ = id;
   }
 
+  void GetDisplayedNotifications(
+      GetDisplayedNotificationsCallback callback) override {}
+
   int display_count_ = 0;
   std::string last_display_id_;
   crosapi::mojom::NotificationPtr last_notification_;

chromeos/crosapi/mojom/message_center.mojom

@@ -20,6 +20,11 @@ interface MessageCenter {
 
   // Closes a notification by the ID provided in |notification| above.
   CloseNotification@1(string id);
+
+  // Returns the IDs of the currently-displayed notifications. Order within the
+  // array is not guaranteed. Mojo does not support sets.
+  [MinVersion=1]
+  GetDisplayedNotifications@2() => (array<string> ids);
 };
 
 // Handles responses to user actions on notifications. Multiple actions may