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

chrome/browser/ui/chrome_pages.cc

Index: chrome/browser/ui/chrome_pages.cc
diff --git a/chrome/browser/ui/chrome_pages.cc b/chrome/browser/ui/chrome_pages.cc
index f0b002e9e91e0e31389f78b63659c7bd956043d8..ccfbac461fb8e645b47a66211927e0dd1b331015 100644
--- a/chrome/browser/ui/chrome_pages.cc
+++ b/chrome/browser/ui/chrome_pages.cc
@@ -15,6 +15,7 @@
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_navigator.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/settings_window_manager.h"
@@ -25,8 +26,10 @@
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
+#include "extensions/common/constants.h"
 #include "google_apis/gaia/gaia_urls.h"
 #include "net/base/url_util.h"
+#include "ui/base/window_open_disposition.h"
 
 #if defined(OS_WIN)
 #include "chrome/browser/enumerate_modules_model_win.h"
@@ -82,18 +85,22 @@ void ShowHelpImpl(Browser* browser,
       extensions::ExtensionRegistry::Get(profile)->GetExtensionById(
           genius_app::kGeniusAppId,
           extensions::ExtensionRegistry::EVERYTHING);
-  AppLaunchParams params(profile, extension, 0, host_desktop_type);
+  extensions::AppLaunchSource app_launch_source(extensions::SOURCE_UNTRACKED);
   switch (source) {
     case HELP_SOURCE_KEYBOARD:
-      params.source = extensions::SOURCE_KEYBOARD;
+      app_launch_source = extensions::SOURCE_KEYBOARD;
       break;
     case HELP_SOURCE_MENU:
-      params.source = extensions::SOURCE_SYSTEM_TRAY;
+      app_launch_source = extensions::SOURCE_SYSTEM_TRAY;
       break;
     case HELP_SOURCE_WEBUI:
-      params.source = extensions::SOURCE_ABOUT_PAGE;
+      app_launch_source = extensions::SOURCE_ABOUT_PAGE;
       break;
+    default:
+      NOTREACHED() << "Unhandled help source" << source;
   }
+  AppLaunchParams params(profile, extension, CURRENT_TAB, host_desktop_type,
+                         app_launch_source);
   OpenApplication(params);
 #else
   GURL url;