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

extensions/renderer/resources/app_runtime_custom_bindings.js

Index: extensions/renderer/resources/app_runtime_custom_bindings.js
diff --git a/extensions/renderer/resources/app_runtime_custom_bindings.js b/extensions/renderer/resources/app_runtime_custom_bindings.js
index 5910d6e95f3dc781b85199900b729376d9715b1a..9dbaf07b854671cd9b3db5142626ce47f26aa4e3 100644
--- a/extensions/renderer/resources/app_runtime_custom_bindings.js
+++ b/extensions/renderer/resources/app_runtime_custom_bindings.js
@@ -47,7 +47,10 @@ eventBindings.registerArgumentMassager('app.runtime.onLaunched',
         $Array.push(items, item);
       }
       if (--numItems === 0) {
-        var data = { isKioskSession: launchData.isKioskSession };
+        var data = {
+          isKioskSession: launchData.isKioskSession,
+          source: launchData.source
+        };
         if (items.length !== 0) {
           data.id = launchData.id;
           data.items = items;