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

chrome/browser/ui/ash/chrome_new_window_delegate_chromeos.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/ash/chrome_new_window_delegate_chromeos.h"
 
 #include "ash/keyboard_overlay/keyboard_overlay_view.h"
 #include "chrome/browser/chromeos/file_manager/app_id.h"
 #include "chrome/browser/extensions/api/terminal/terminal_extension_helper.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/extensions/app_launch_params.h"
 #include "chrome/browser/ui/extensions/application_launch.h"
 #include "chrome/browser/ui/scoped_tabbed_browser_displayer.h"
 #include "chrome/browser/ui/webui/chrome_web_contents_handler.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/extension_system.h"
+#include "extensions/common/constants.h"
+#include "ui/base/window_open_disposition.h"
 
 ChromeNewWindowDelegateChromeos::ChromeNewWindowDelegateChromeos() {}
 ChromeNewWindowDelegateChromeos::~ChromeNewWindowDelegateChromeos() {}
 
 void ChromeNewWindowDelegateChromeos::OpenFileManager() {
   using file_manager::kFileManagerAppId;
   Profile* const profile = ProfileManager::GetActiveUserProfile();
   const ExtensionService* const service =
       extensions::ExtensionSystem::Get(profile)->extension_service();
   if (!service ||
       !extensions::util::IsAppLaunchableWithoutEnabling(kFileManagerAppId,
                                                         profile)) {
     return;
   }
 
   const extensions::Extension* const extension =
       service->GetInstalledExtension(kFileManagerAppId);
-  // event_flags = 0 means this invokes the same behavior as the launcher
-  // item is clicked without any keyboard modifiers.
-  OpenApplication(AppLaunchParams(profile,
-                                  extension,
-                                  0 /* event_flags */,
-                                  chrome::HOST_DESKTOP_TYPE_ASH));
+  OpenApplication(AppLaunchParams(profile, extension, CURRENT_TAB,
+                                  chrome::HOST_DESKTOP_TYPE_ASH,
+                                  extensions::SOURCE_CHROME_INTERNAL));
 }
 
 void ChromeNewWindowDelegateChromeos::OpenCrosh() {
   Profile* profile = ProfileManager::GetActiveUserProfile();
   GURL crosh_url = extensions::TerminalExtensionHelper::GetCroshExtensionURL(
       profile);
   if (!crosh_url.is_valid())
     return;
   chrome::ScopedTabbedBrowserDisplayer displayer(
       profile,
@@ skipping 11 matching lines @@
 }
 
 void ChromeNewWindowDelegateChromeos::ShowKeyboardOverlay() {
   // TODO(mazda): Move the show logic to ash (http://crbug.com/124222).
   Profile* profile = ProfileManager::GetActiveUserProfile();
   std::string url(chrome::kChromeUIKeyboardOverlayURL);
   ash::KeyboardOverlayView::ShowDialog(profile,
                                        new ChromeWebContentsHandler,
                                        GURL(url));
 }