Make "source" a required argument of AppLaunchParams and fill in the argument in all call points.

chrome/browser/apps/ephemeral_app_launcher.cc

Index: chrome/browser/apps/ephemeral_app_launcher.cc
diff --git a/chrome/browser/apps/ephemeral_app_launcher.cc b/chrome/browser/apps/ephemeral_app_launcher.cc
index a1f516b572912dba72d254dcb73367b0a7aac835..643f633baf6a9beeb4174d9744fdc18a05e6457b 100644
--- a/chrome/browser/apps/ephemeral_app_launcher.cc
+++ b/chrome/browser/apps/ephemeral_app_launcher.cc
@@ -11,6 +11,7 @@
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_navigator.h"
+#include "chrome/browser/ui/extensions/app_launch_params.h"
 #include "chrome/browser/ui/extensions/application_launch.h"
 #include "chrome/browser/ui/extensions/extension_enable_flow.h"
 #include "chrome/browser/ui/native_window_tracker.h"
@@ -22,6 +23,7 @@
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/management_policy.h"
+#include "extensions/common/constants.h"
 #include "extensions/common/permissions/permissions_data.h"
 
 using content::WebContents;
@@ -279,7 +281,8 @@ void EphemeralAppLauncher::LaunchApp(const Extension* extension) const {
          ExtensionRegistry::Get(profile())
              ->GetExtensionById(extension->id(), ExtensionRegistry::ENABLED));
 
-  AppLaunchParams params(profile(), extension, NEW_FOREGROUND_TAB);
+  AppLaunchParams params(profile(), extension, NEW_FOREGROUND_TAB,
+                         extensions::SOURCE_EPHEMERAL_APP);
   params.desktop_type =
       chrome::GetHostDesktopTypeForNativeWindow(parent_window_);
   OpenApplication(params);