Add a generic template for system info provider

chrome/browser/extensions/api/system_info_cpu/system_info_cpu_api.cc

 // 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.
+
 #include "chrome/browser/extensions/api/system_info_cpu/system_info_cpu_api.h"
 
-#include "base/logging.h"
-#include "content/public/browser/browser_thread.h"
 #include "chrome/browser/extensions/api/system_info_cpu/cpu_info_provider.h"
 
 namespace extensions {
+
 using api::experimental_system_info_cpu::CpuInfo;
-using api::experimental_system_info_cpu::CpuCoreInfo;
-using content::BrowserThread;
 
 SystemInfoCpuGetFunction::SystemInfoCpuGetFunction() {
 }
 
 SystemInfoCpuGetFunction::~SystemInfoCpuGetFunction() {
-  // Delete the provider that was created on FILE thread.
-  BrowserThread::DeleteSoon(BrowserThread::FILE, FROM_HERE, provider_);
 }
 
 bool SystemInfoCpuGetFunction::RunImpl() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-    base::Bind(&SystemInfoCpuGetFunction::WorkOnFileThread, this));
+  CpuInfoProvider::Get()->StartQueryInfo(
+      base::Bind(&SystemInfoCpuGetFunction::OnGetCpuInfoCompleted, this));
   return true;
 }
 
-void SystemInfoCpuGetFunction::WorkOnFileThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-  provider_ = CpuInfoProvider::Create();
-  GetCpuInfoOnFileThread();
-}
-
-void SystemInfoCpuGetFunction::GetCpuInfoOnFileThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-  bool success = false;
-
-  CpuInfo info;
-  if (provider_ && provider_->GetCpuInfo(&info)) {
+void SystemInfoCpuGetFunction::OnGetCpuInfoCompleted(const CpuInfo& info,
+    bool success) {
+  if (success)
     SetResult(info.ToValue().release());
-    success = true;
-  } else {
-    SetError("Error in querying cpu information!");
-  }
-  // Respond on UI thread.
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(&SystemInfoCpuGetFunction::RespondOnUIThread, this, success));
-}
-
-
-void SystemInfoCpuGetFunction::RespondOnUIThread(bool success) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  else
+    SetError("Error occurred when querying cpu information.");
   SendResponse(success);
 }
 
-// A mock implementation of CpuInfoProver for temporary usage.
-// Will be moved out when the platform specific implementation are done.
-class MockCpuInfoProvider : public CpuInfoProvider {
- public:
-  MockCpuInfoProvider() {}
-  virtual ~MockCpuInfoProvider() {}
-  virtual bool GetCpuInfo(CpuInfo* info) OVERRIDE;
-};
-
-bool MockCpuInfoProvider::GetCpuInfo(CpuInfo* info) {
-  if (!info) return false;
-  linked_ptr<CpuCoreInfo> core(new CpuCoreInfo());
-  core->load = 53;
-  info->cores.push_back(core);
-  return true;
-}
-
-// static
-CpuInfoProvider* CpuInfoProvider::Create() {
-  return new MockCpuInfoProvider();
-}
-
 }  // namespace extensions