Add unittest for ArcNotificationContentView

chrome/browser/chrome_browser_main_extra_parts_exo.h

Index: chrome/browser/chrome_browser_main_extra_parts_exo.h
diff --git a/chrome/browser/chrome_browser_main_extra_parts_exo.h b/chrome/browser/chrome_browser_main_extra_parts_exo.h
index 7e97f85d8065ee5cf2901ad29a625265c223c8da..0113c7713780470b6f7adc8583a5a6b2799aadb3 100644
--- a/chrome/browser/chrome_browser_main_extra_parts_exo.h
+++ b/chrome/browser/chrome_browser_main_extra_parts_exo.h
@@ -19,7 +19,7 @@ class Server;
 }
 
 namespace arc {
-class ArcNotificationSurfaceManager;
+class ArcNotificationSurfaceManagerImpl;
 }
 
 class ChromeBrowserMainExtraPartsExo : public ChromeBrowserMainExtraParts {
@@ -32,7 +32,7 @@ class ChromeBrowserMainExtraPartsExo : public ChromeBrowserMainExtraParts {
   void PostMainMessageLoopRun() override;
 
  private:
-  std::unique_ptr<arc::ArcNotificationSurfaceManager>
+  std::unique_ptr<arc::ArcNotificationSurfaceManagerImpl>
       arc_notification_surface_manager_;
   std::unique_ptr<exo::WMHelper> wm_helper_;
   std::unique_ptr<exo::Display> display_;