Make app launcher Chrome Store UMA consistent with NTP.

chrome/common/extensions/extension_constants.h

Index: chrome/common/extensions/extension_constants.h
diff --git a/chrome/common/extensions/extension_constants.h b/chrome/common/extensions/extension_constants.h
index 9566f17952f28875d5bef2fad2a3f337f7fbf028..f55cca73dbedf4bb452c7f627ebbc7d6ea3bb408 100644
--- a/chrome/common/extensions/extension_constants.h
+++ b/chrome/common/extensions/extension_constants.h
@@ -255,6 +255,18 @@ namespace extension_misc {
     // User clicked app launcher search result.
     APP_LAUNCH_APP_LIST_SEARCH,
 
+    // User clicked the chrome app icon from the app launcher's main view.
+    APP_LAUNCH_APP_LIST_MAIN_CHROME,
+
+    // User clicked the webstore icon from the app launcher's main view.
+    APP_LAUNCH_APP_LIST_MAIN_WEBSTORE,
+
+    // User clicked the chrome app icon from the app launcher's search view.
+    APP_LAUNCH_APP_LIST_SEARCH_CHROME,
+
+    // User clicked the webstore icon from the app launcher's search view.
+    APP_LAUNCH_APP_LIST_SEARCH_WEBSTORE,
+
     APP_LAUNCH_BUCKET_BOUNDARY,
     APP_LAUNCH_BUCKET_INVALID
   };