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

chrome/browser/ui/extensions/app_launch_params.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_EXTENSIONS_APP_LAUNCH_PARAMS_H_
 #define CHROME_BROWSER_UI_EXTENSIONS_APP_LAUNCH_PARAMS_H_
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "chrome/common/extensions/extension_constants.h"
+#include "extensions/common/constants.h"
 #include "ui/base/window_open_disposition.h"
 #include "ui/gfx/rect.h"
 #include "url/gurl.h"
 
 class Profile;
 
 namespace extensions {
 class Extension;
 }
 
@@ skipping 42 matching lines @@
   // position and dimensions.
   gfx::Rect override_bounds;
 
   // If non-empty, information from the command line may be passed on to the
   // application.
   base::CommandLine command_line;
 
   // If non-empty, the current directory from which any relative paths on the
   // command line should be expanded from.
   base::FilePath current_directory;
+
+  // Record where the app is launched from for tracking purpose.
+  // Different app may have their own enumeration of sources.
+  extensions::AppLaunchSource source;
 };
 
 #endif  // CHROME_BROWSER_UI_EXTENSIONS_APP_LAUNCH_PARAMS_H_