Add a generic template for system info provider

chrome/browser/extensions/api/system_info_cpu/system_info_cpu_apitest.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 "base/command_line.h"
+#include "base/message_loop.h"
+#include "chrome/browser/extensions/api/system_info_cpu/cpu_info_provider.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/common/chrome_switches.h"
 
 namespace extensions {
+
+using api::experimental_system_info_cpu::CpuInfo;
+using api::experimental_system_info_cpu::CpuCoreInfo;
+
+class MockCpuInfoProviderImpl : public CpuInfoProvider {
+ public:
+  MockCpuInfoProviderImpl() {}
+  ~MockCpuInfoProviderImpl() {}
+
+  virtual bool QueryInfo(CpuInfo* info) OVERRIDE {
+    DCHECK(info);
+
+    info->cores.clear();
+
+    static const unsigned int kNumberOfCores = 4;
+    for (unsigned int i = 0; i < kNumberOfCores; ++i) {
+      linked_ptr<CpuCoreInfo> core(new CpuCoreInfo());
+      core->load = i*10;
+      info->cores.push_back(core);
+    }
+    return true;
+  }
+};
+
 class SystemInfoCpuApiTest: public ExtensionApiTest {
  public:
   SystemInfoCpuApiTest() {}
   ~SystemInfoCpuApiTest() {}
+
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     ExtensionApiTest::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kEnableExperimentalExtensionApis);
   }
+
+  virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
+    ExtensionApiTest::SetUpInProcessBrowserTestFixture();
+    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+
+    CpuInfoProvider* provider = new MockCpuInfoProviderImpl();
+    // The provider is owned by the single CpuInfoProvider instance.
+    CpuInfoProvider::InitializeForTesting(provider);
+  }
+
+ private:
+  scoped_ptr<MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoCpuApiTest, Cpu) {
   ASSERT_TRUE(RunExtensionTest("systeminfo/cpu")) << message_;
 }
 
 }  // namespace extensions