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

chrome/browser/ui/extensions/application_launch.h

Index: chrome/browser/ui/extensions/application_launch.h
diff --git a/chrome/browser/ui/extensions/application_launch.h b/chrome/browser/ui/extensions/application_launch.h
index 5f07ae0c5ae7391cb07da7c1548b950434d2599e..54bfd5ad8c8833be0189e1810587adbb6402081a 100644
--- a/chrome/browser/ui/extensions/application_launch.h
+++ b/chrome/browser/ui/extensions/application_launch.h
@@ -9,6 +9,7 @@
 #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"
@@ -80,6 +81,10 @@ struct AppLaunchParams {
   // 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;
 };
 
 // Opens the application, possibly prompting the user to re-enable it.