Add the implementation skeleton for systeminfo.cpu API

chrome/common/extensions/api/experimental_system_info_cpu.idl

+// Copyright (c) 2012 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.
+
+// File-level comment to appease parser. Eventually this will not be necessary.
+namespace experimental.systemInfo.cpu {
+
+  dictionary CpuCoreInfo {
+    // Indicates the load of CPU core, as a number between 0 and 100.
+    long load;
+  };
+  
+  dictionary CpuInfo {
+    // The array of the CPU processors in the system.
+    CpuCoreInfo[] cores;
+  };
+
+  callback CpuInfoCallback = void (CpuInfo prop);
+  callback CpuUpdateCallback = void (ChangeInfo info);
+  
+  interface Functions {
+    // Get CPU property.
+    static void get(CpuInfoCallback callback);
+  };
+};