Check in Data Saver extension into Chromium

chrome/test/data/chromeproxy/extension/background_compiled.js

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+chrome.runtime.onInstalled.addListener(
+  function(a){
+    console.log("chrome.runtime.onInstalled details: "+JSON.stringify(a));
+    console.log("typeof chrome.dataReductionProxy: "+
+                typeof chrome.dataReductionProxy);
+    if("undefined"!=typeof chrome.dataReductionProxy)
+      if("install"==a.reason)chrome.dataReductionProxy.spdyProxyEnabled.set(
+                               {value:!0}),
+      "clearDataSavings"in chrome.dataReductionProxy&&
+        chrome.dataReductionProxy.clearDataSavings(),
+      showEnabledIcon();
+      else if("update"==a.reason||"chrome_update"==a.reason)
+        showEnabledIconIfProxyOn(),
+        chrome.storage.local.get("user_enabled_proxy",
+        function(a){"user_enabled_proxy"in a&&(
+          chrome.dataReductionProxy.spdyProxyEnabled.set({value:!0}),
+          showEnabledIcon(),
+          chrome.storage.local.remove("user_enabled_proxy"))})});
+      chrome.runtime.onStartup.addListener(function(){
+      showEnabledIconIfProxyOn()});chrome.tabs.onCreated.addListener(
+      function(a){setTimeout(function(){a.incognito&&
+      chrome.browserAction.setIcon({tabId:a.id,path:{
+        19:"./images/proxy-disabled19.png",
+        38:"./images/proxy-disabled38.png"}})},500)});
+function showEnabledIconIfProxyOn(){
+  "undefined"!=typeof chrome.dataReductionProxy&&(
+    console.log("Calling spdyProxyEnabled.get"),
+    chrome.dataReductionProxy.spdyProxyEnabled.get({},
+      function(a){
+        console.log("chrome.dataReductionProxy.spdyProxyEnabled.get: "
+                    +JSON.stringify(a));
+        (a="value"in a&&a.value)&&showEnabledIcon()
+      })
+  )
+};
+function showEnabledIcon(){
+  console.log("Calling chrome.browserAction.setIcon");
+  chrome.browserAction.setIcon({path:{19:"./images/proxy-enabled19.webp",
+                                      38:"./images/proxy-enabled38.webp"}})
+};