extensions: Add CPU temperatures field to system.cpu.getInfo() function

extensions/test/data/system/cpu/test_cpu_api.js

 // Copyright 2013 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.
 
 // system.cpu.getInfo api test
 // extensions_browsertests --gtest_filter=SystemCpuApiTest.*
 
 chrome.test.runTests([
   function testGet() {
     var expectedProcessors = [{
       usage: {
         kernel: 1,
         user: 2,
         idle: 3,
         total: 6
       }
     }];
     for(var i = 0; i < 20; ++i) {
       chrome.system.cpu.getInfo(chrome.test.callbackPass(function(result) {
         chrome.test.assertEq(4, result.numOfProcessors);
         chrome.test.assertEq("x86", result.archName);
         chrome.test.assertEq("unknown", result.modelName);
         chrome.test.assertEq(["mmx", "avx"], result.features);
         chrome.test.assertEq(expectedProcessors, result.processors);
+        chrome.test.assertEq([30.125, 40.0625], result.temperatures);
       }));
     }
   }
 ]);