PlatformNotificationService layering cleanup.

chrome/test/base/testing_browser_process.cc

Index: chrome/test/base/testing_browser_process.cc
diff --git a/chrome/test/base/testing_browser_process.cc b/chrome/test/base/testing_browser_process.cc
index 42eb41fc1251dccd41131a50b6a5eab2dc2778df..b726f65e0f6b1761d5b76097a16deaa3c48600f8 100644
--- a/chrome/test/base/testing_browser_process.cc
+++ b/chrome/test/base/testing_browser_process.cc
@@ -11,6 +11,7 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_impl.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
+#include "chrome/browser/notifications/notification_platform_bridge.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/printing/print_job_manager.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -227,7 +228,7 @@ NotificationUIManager* TestingBrowserProcess::notification_ui_manager() {
 
 NotificationPlatformBridge*
 TestingBrowserProcess::notification_platform_bridge() {
-  return nullptr;
+  return notification_platform_bridge_.get();
 }
 
 message_center::MessageCenter* TestingBrowserProcess::message_center() {
@@ -383,6 +384,11 @@ void TestingBrowserProcess::SetNotificationUIManager(
   notification_ui_manager_.swap(notification_ui_manager);
 }
 
+void TestingBrowserProcess::SetNotificationPlatformBridge(
+    std::unique_ptr<NotificationPlatformBridge> notification_platform_bridge) {
+  notification_platform_bridge_.swap(notification_platform_bridge);
+}
+
 void TestingBrowserProcess::SetLocalState(PrefService* local_state) {
   if (!local_state) {
     // The local_state_ PrefService is owned outside of TestingBrowserProcess,