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

extensions/common/constants.h

Index: extensions/common/constants.h
diff --git a/extensions/common/constants.h b/extensions/common/constants.h
index 25d0be23f9f2880e50f2b1fc1f09ab410400a2d5..a97f47c0a7ef54e426098cf822d72690812b9aa4 100644
--- a/extensions/common/constants.h
+++ b/extensions/common/constants.h
@@ -126,6 +126,13 @@ enum AppLaunchSource {
   SOURCE_ABOUT_PAGE,
   SOURCE_KEYBOARD,
 
+  SOURCE_SETTINGS_PAGE,
+  SOURCE_MANAGEMENT_API,
+  SOURCE_EPHEMERAL,
+  SOURCE_BACKGROUND,
+  SOURCE_KIOSK,
+  SOURCE_CHROME_INTERNAL,
+
   NUM_APP_LAUNCH_SOURCES
 };