Revert "Rename extension references to Chromium"

This reverts commit ef7aca33f7.

popup.html

@@ -3,7 +3,7 @@
   <head>
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
-    <title>Xget for Chromium</title>
+    <title>Xget for Chrome</title>
     <style>
       body {
         width: 380px;
@@ -211,7 +211,7 @@
   </head>
   <body>
     <div class="header">
-      <h1>Xget for Chromium</h1>
+      <h1>Xget for Chrome</h1>
       <div class="subtitle">下载加速器</div>
     </div>