Add a new field "source" in launchData of chrome.app.runtime.onLaunched() to trace launch source.

chrome/browser/ui/chrome_pages.cc

 // Copyright (c) 2012 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/chrome_pages.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
@@ skipping 64 matching lines @@
 void ShowHelpImpl(Browser* browser,
                   Profile* profile,
                   HostDesktopType host_desktop_type,
                   HelpSource source) {
   content::RecordAction(UserMetricsAction("ShowHelpTab"));
 #if defined(OS_CHROMEOS) && defined(OFFICIAL_BUILD)
   const extensions::Extension* extension =
       extensions::ExtensionRegistry::Get(profile)->GetExtensionById(
           genius_app::kGeniusAppId,
           extensions::ExtensionRegistry::EVERYTHING);
-  OpenApplication(AppLaunchParams(profile, extension, 0, host_desktop_type));
+  AppLaunchParams params(profile, extension, 0, host_desktop_type);
+  switch (source) {
+    case HELP_SOURCE_KEYBOARD:
+      params.source = extensions::SOURCE_KEYBOARD;
+      break;
+    case HELP_SOURCE_MENU:
+      params.source = extensions::SOURCE_SYSTEM_TRAY;
+      break;
+    case HELP_SOURCE_WEBUI:
+      params.source = extensions::SOURCE_ABOUT_PAGE;
+      break;
+  }
+  OpenApplication(params);
 #else
   GURL url;
   switch (source) {
     case HELP_SOURCE_KEYBOARD:
       url = GURL(kChromeHelpViaKeyboardURL);
       break;
     case HELP_SOURCE_MENU:
       url = GURL(kChromeHelpViaMenuURL);
       break;
     case HELP_SOURCE_WEBUI:
@@ skipping 228 matching lines @@
       browser = displayer->browser();
     }
 
     NavigateToSingletonTab(browser, GURL(signin::GetPromoURL(source, false)));
     DCHECK_GT(browser->tab_strip_model()->count(), 0);
   }
 }
 #endif
 
 }  // namespace chrome