[chrome-gnome-shell/feature/extensions_sync] Use constants for signals names

[Yuri Konotopov <ykonotopov src gnome org>]

commit 6f18f0908017cd089223fa6b9c83379bda1a91d9
Author: Yuri Konotopov <ykonotopov gmail com>
Date:   Wed Aug 10 19:24:52 2016 +0300

    Use constants for signals names

 extension/content-script-start.js |    2 +-
 extension/extension.js            |    2 +-
 extension/include/constants.js    |    3 +++
 3 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/extension/content-script-start.js b/extension/content-script-start.js
index e39367d..36a2649 100644
--- a/extension/content-script-start.js
+++ b/extension/content-script-start.js
@@ -61,7 +61,7 @@ chrome.runtime.onMessage.addListener(
        function (request, sender, sendResponse) {
                if(
                        sender.id && sender.id === GS_CHROME_ID &&
-                       request && request.signal && ["ExtensionStatusChanged", 
"org.gnome.Shell"].indexOf(request.signal) !== -1)
+                       request && request.signal && [SIGNAL_EXTENSIONS_CHANGED, 
SIGNAL_SHELL_APPEARED].indexOf(request.signal) !== -1)
                {
                        window.postMessage(
                                {
diff --git a/extension/extension.js b/extension/extension.js
index 007e6d9..3421ec2 100644
--- a/extension/extension.js
+++ b/extension/extension.js
@@ -69,7 +69,7 @@ chrome.runtime.onMessageExternal.addListener(function (request, sender, sendResp
 
 var port = chrome.runtime.connectNative(NATIVE_HOST);
 port.onMessage.addListener(function (message) {
-       if (message && message.signal && ["ExtensionStatusChanged", 
"org.gnome.Shell"].indexOf(message.signal) !== -1)
+       if (message && message.signal && [SIGNAL_EXTENSIONS_CHANGED, 
SIGNAL_SHELL_APPEARED].indexOf(message.signal) !== -1)
        {
                chrome.tabs.query({
                        url: EXTENSIONS_WEBSITE + '*'
diff --git a/extension/include/constants.js b/extension/include/constants.js
index 4bc8dc6..8be9447 100644
--- a/extension/include/constants.js
+++ b/extension/include/constants.js
@@ -19,6 +19,9 @@ ALARM_UPDATE_CHECK                    = 'gs-chrome-update-check';
 
 MESSAGE_NEXT_UPDATE_CHANGED            = 'gs-next-update-changed';
 
+SIGNAL_EXTENSIONS_CHANGED              = 'ExtensionStatusChanged';
+SIGNAL_SHELL_APPEARED                  = 'org.gnome.Shell';
+
 NATIVE_HOST                            = 'io.github.ne0sight.gs_chrome_connector';
 
 EXTENSIONS_WEBSITE                     = 'https://extensions.gnome.org/';