Polish the SystemInfoProvider template code and refactor StorageInfoProvider based on it.

BUG=136519
TEST=browser_tests --gtest_filter=SystemInfoStorageApiTest.*

Review URL: https://chromiumcodereview.appspot.com/10876041

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153163 0039d316-1c4b-4281-b951-d872f2087c98

14 files changed, 238 insertions, 148 deletions

diff --git a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider.h b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider.h
index b0cb12f..5a714db 100644
--- a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider.h
+++ b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider.h
@@ -9,8 +9,14 @@
 
 namespace extensions {
 
-typedef SystemInfoProvider<api::experimental_system_info_cpu::CpuInfo>
-    CpuInfoProvider;
+class CpuInfoProvider
+    : public SystemInfoProvider<api::experimental_system_info_cpu::CpuInfo> {
+ public:
+  virtual ~CpuInfoProvider() {}
+
+  // Return the single shared instance of CpuInfoProvider.
+  static CpuInfoProvider* Get();
+};
 
 }  // namespace extensions
 
diff --git a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_linux.cc b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_linux.cc
index c8d6c6c..80c1995 100644
--- a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_linux.cc
+++ b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_linux.cc
@@ -6,6 +6,8 @@
 
 namespace extensions {
 
+namespace {
+
 using api::experimental_system_info_cpu::CpuInfo;
 
 // CpuInfoProvider implementation for Linux platform.
@@ -21,8 +23,9 @@ bool CpuInfoProviderLinux::QueryInfo(CpuInfo* info) {
   return false;
 }
 
+}  // namespace
+
 // static
-template<>
 CpuInfoProvider* CpuInfoProvider::Get() {
   return CpuInfoProvider::GetInstance<CpuInfoProviderLinux>();
 }
diff --git a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_mac.cc b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_mac.cc
index 3010d6e..7f43b00 100644
--- a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_mac.cc
+++ b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_mac.cc
@@ -6,6 +6,8 @@
 
 namespace extensions {
 
+namespace {
+
 using api::experimental_system_info_cpu::CpuInfo;
 
 // CpuInfoProvider implementation on Mac OS.
@@ -21,8 +23,9 @@ bool CpuInfoProviderMac::QueryInfo(CpuInfo* info) {
   return false;
 }
 
+}  // namespace
+
 // static
-template<>
 CpuInfoProvider* CpuInfoProvider::Get() {
   return CpuInfoProvider::GetInstance<CpuInfoProviderMac>();
 }
diff --git a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_win.cc b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_win.cc
index eb51d3d..d1929a2 100644
--- a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_win.cc
+++ b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_win.cc
@@ -6,6 +6,8 @@
 
 namespace extensions {
 
+namespace {
+
 using api::experimental_system_info_cpu::CpuInfo;
 
 // CpuInfoProvider implementation on Windows platform.
@@ -21,8 +23,9 @@ bool CpuInfoProviderWin::QueryInfo(CpuInfo* info) {
   return false;
 }
 
+}  // namespace
+
 // static
-template<>
 CpuInfoProvider* CpuInfoProvider::Get() {
   return CpuInfoProvider::GetInstance<CpuInfoProviderWin>();
 }
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider.h b/chrome/browser/extensions/api/system_info_storage/storage_info_provider.h
index 18f0e6f..0265ddd 100644
--- a/chrome/browser/extensions/api/system_info_storage/storage_info_provider.h
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider.h
@@ -4,14 +4,15 @@
 #ifndef CHROME_BROWSER_EXTENSIONS_API_SYSTEM_INFO_STORAGE_STORAGE_INFO_PROVIDER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_SYSTEM_INFO_STORAGE_STORAGE_INFO_PROVIDER_H_
 
+#include "chrome/browser/extensions/system_info_provider.h"
 #include "chrome/common/extensions/api/experimental_system_info_storage.h"
 
 namespace extensions {
 namespace systeminfo {
 
-// TODO(hmin): Here the storage type is declared as string type due to the IDL
-// doesn't support enum type yet. Once http://crbug.com/141940 is fixed, we
-// could reuse enum values generated by IDL compiler.
+// TODO(hongbo): Here the storage type is declared as string type due to the
+// IDL doesn't support enum type yet. Once http://crbug.com/141940 is fixed,
+// we could reuse enum values generated by IDL compiler.
 
 // Unknown storage type.
 extern const char kStorageTypeUnknown[];
@@ -19,21 +20,22 @@ extern const char kStorageTypeUnknown[];
 extern const char kStorageTypeHardDisk[];
 // Removable storage, e.g. USB device, flash card reader.
 extern const char kStorageTypeRemovable[];
+
 }  // namespace systeminfo
 
-// An interface for retrieving storage information on different platforms.
-class StorageInfoProvider {
+class StorageInfoProvider
+    : public SystemInfoProvider<
+          api::experimental_system_info_storage::StorageInfo> {
  public:
-   // Return a StorageInfoProvider instance. The caller is responsible for
-   // destroying it.
-   static StorageInfoProvider* Create();
+  virtual ~StorageInfoProvider() {}
 
-   virtual ~StorageInfoProvider() {}
+  // Get the single shared instance of StorageInfoProvider.
+  static StorageInfoProvider* Get();
 
-   // Return true if succeed to get storage information. Should be implemented
-   // on different platforms.
-   virtual bool GetStorageInfo(
-       api::experimental_system_info_storage::StorageInfo* info) = 0;
+  // Get the information for the storage unit specified by the |id| parameter,
+  // and output the result to the |info|.
+  virtual bool QueryUnitInfo(const std::string& id,
+      api::experimental_system_info_storage::StorageUnitInfo* info) = 0;
 };
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_linux.cc b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_linux.cc
new file mode 100644
index 0000000..43790f9
--- /dev/null
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_linux.cc
@@ -0,0 +1,42 @@
+// 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_storage/storage_info_provider.h"
+
+namespace extensions {
+
+namespace {
+
+using api::experimental_system_info_storage::StorageInfo;
+using api::experimental_system_info_storage::StorageUnitInfo;
+
+// StorageInfoProvider implementation on Linux platform.
+// TODO(hongbo): not implemented yet.
+class StorageInfoProviderLinux : public StorageInfoProvider {
+ public:
+  StorageInfoProviderLinux() {}
+  virtual ~StorageInfoProviderLinux() {}
+
+  virtual bool QueryInfo(StorageInfo* info) OVERRIDE;
+  virtual bool QueryUnitInfo(const std::string& id,
+                             StorageUnitInfo* info) OVERRIDE;
+};
+
+bool StorageInfoProviderLinux::QueryInfo(StorageInfo* info) {
+  return false;
+}
+
+bool StorageInfoProviderLinux::QueryUnitInfo(const std::string& id,
+                                             StorageUnitInfo* info) {
+  return false;
+}
+
+}   // namespace
+
+// static
+StorageInfoProvider* StorageInfoProvider::Get() {
+  return StorageInfoProvider::GetInstance<StorageInfoProviderLinux>();
+}
+
+}  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc
new file mode 100644
index 0000000..2c7f555
--- /dev/null
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc
@@ -0,0 +1,42 @@
+// 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_storage/storage_info_provider.h"
+
+namespace extensions {
+
+namespace {
+
+using api::experimental_system_info_storage::StorageInfo;
+using api::experimental_system_info_storage::StorageUnitInfo;
+
+// StorageInfoProvider implementation on Macdows platform.
+// TODO(hongbo): not implemented yet.
+class StorageInfoProviderMac : public StorageInfoProvider {
+ public:
+  StorageInfoProviderMac() {}
+  virtual ~StorageInfoProviderMac() {}
+
+  virtual bool QueryInfo(StorageInfo* info) OVERRIDE;
+  virtual bool QueryUnitInfo(const std::string& id,
+                             StorageUnitInfo* info) OVERRIDE;
+};
+
+bool StorageInfoProviderMac::QueryInfo(StorageInfo* info) {
+  return false;
+}
+
+bool StorageInfoProviderMac::QueryUnitInfo(const std::string& id,
+                                           StorageUnitInfo* info) {
+  return false;
+}
+
+}  // namespace
+
+// static
+StorageInfoProvider* StorageInfoProvider::Get() {
+  return StorageInfoProvider::GetInstance<StorageInfoProviderMac>();
+}
+
+}  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc
index 524ba82..66a3ebb 100644
--- a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc
@@ -5,11 +5,13 @@
 #include "chrome/browser/extensions/api/system_info_storage/storage_info_provider.h"
 
 #include "base/string_util.h"
-
+#include "base/utf_string_conversions.h"
 #include <windows.h>
 
 namespace extensions {
 
+namespace {
+
 using api::experimental_system_info_storage::StorageInfo;
 using api::experimental_system_info_storage::StorageUnitInfo;
 
@@ -20,26 +22,16 @@ const unsigned long kMaxLogicalDriveString = 4 * 26;
 // StorageInfoProvider implementation on Windows platform.
 class StorageInfoProviderWin : public StorageInfoProvider {
  public:
-  StorageInfoProviderWin();
-  virtual ~StorageInfoProviderWin();
+  StorageInfoProviderWin() {}
+  virtual ~StorageInfoProviderWin() {}
 
-  virtual bool GetStorageInfo(StorageInfo* info) OVERRIDE;
+  virtual bool QueryInfo(StorageInfo* info) OVERRIDE;
+  virtual bool QueryUnitInfo(const std::string& id,
+                             StorageUnitInfo* info) OVERRIDE;
 };
 
-// static
-StorageInfoProvider* StorageInfoProvider::Create() {
-  return new StorageInfoProviderWin();
-}
-
-// StorageInfoProviderWin implementation.
-StorageInfoProviderWin::StorageInfoProviderWin() {
-}
-
-StorageInfoProviderWin::~StorageInfoProviderWin() {
-}
-
-bool StorageInfoProviderWin::GetStorageInfo(StorageInfo* info) {
-  if (info == NULL) return false;
+bool StorageInfoProviderWin::QueryInfo(StorageInfo* info) {
+  info->units.clear();
 
   WCHAR logical_drive_strings[kMaxLogicalDriveString];
 
@@ -54,41 +46,57 @@ bool StorageInfoProviderWin::GetStorageInfo(StorageInfo* info) {
 
   // Iterate the drive string by 4 wchars each step
   for (unsigned int i = 0; i < string_length; i += 4) {
-    std::string type;
-    DWORD ret = GetDriveType(&logical_drive_strings[i]);
-    switch (ret) {
-      case DRIVE_FIXED:
-        type = systeminfo::kStorageTypeHardDisk;
-        break;
-      case DRIVE_REMOVABLE:
-        type = systeminfo::kStorageTypeRemovable;
-        break;
-      case DRIVE_UNKNOWN:
-        type = systeminfo::kStorageTypeUnknown;
-        break;
-      case DRIVE_CDROM:       // CD ROM
-      case DRIVE_REMOTE:      // Remote network drive
-      case DRIVE_NO_ROOT_DIR: // Invalid root path
-      case DRIVE_RAMDISK:     // RAM disk
-        // TODO(hmin): Do we need to care about these drive types?
-        continue;
-    }
-
-    ULARGE_INTEGER available_bytes;
-    ULARGE_INTEGER free_bytes;
-    BOOL status = GetDiskFreeSpaceEx(&logical_drive_strings[i], NULL,
-                                     &available_bytes,
-                                     &free_bytes);
-    if (status) {
-      linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
-      unit->id = WideToASCII(string16(&logical_drive_strings[i]));
-      unit->type = type;
-      unit->capacity = static_cast<double>(available_bytes.QuadPart);
-      unit->available_capacity = static_cast<double>(free_bytes.QuadPart);
+    linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
+    if (QueryUnitInfo(WideToUTF8(&logical_drive_strings[i]), unit.get())) {
       info->units.push_back(unit);
     }
   }
   return true;
 }
 
+bool StorageInfoProviderWin::QueryUnitInfo(const std::string& id,
+                                           StorageUnitInfo* info) {
+  DCHECK(info);
+  string16 drive = UTF8ToUTF16(id);
+
+  std::string type;
+  DWORD ret = GetDriveType(drive.c_str());
+  switch (ret) {
+    case DRIVE_FIXED:
+      type = systeminfo::kStorageTypeHardDisk;
+      break;
+    case DRIVE_REMOVABLE:
+      type = systeminfo::kStorageTypeRemovable;
+      break;
+    case DRIVE_UNKNOWN:
+      type = systeminfo::kStorageTypeUnknown;
+      break;
+    case DRIVE_CDROM:       // CD ROM
+    case DRIVE_REMOTE:      // Remote network drive
+    case DRIVE_NO_ROOT_DIR: // Invalid root path
+    case DRIVE_RAMDISK:     // RAM disk
+      // TODO(hmin): Do we need to care about these drive types?
+      return false;
+  }
+
+  ULARGE_INTEGER total_bytes;
+  ULARGE_INTEGER free_bytes;
+
+  if (GetDiskFreeSpaceEx(drive.c_str(), NULL, &total_bytes, &free_bytes)) {
+    info->id = id;
+    info->type = type;
+    info->capacity = static_cast<double>(total_bytes.QuadPart);
+    info->available_capacity = static_cast<double>(free_bytes.QuadPart);
+    return true;
+  }
+  return false;
+}
+
+}  // namespace
+
+// static
+StorageInfoProvider* StorageInfoProvider::Get() {
+  return StorageInfoProvider::GetInstance<StorageInfoProviderWin>();
+}
+
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.cc b/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.cc
index 91916ee..187be39 100644
--- a/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.cc
+++ b/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.cc
@@ -3,21 +3,12 @@
 // found in the LICENSE file.
 #include "chrome/browser/extensions/api/system_info_storage/system_info_storage_api.h"
 
-#include "base/logging.h"
-#include "base/json/json_writer.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/string_number_conversions.h"
-#include "base/string_piece.h"
-#include "base/values.h"
-#include "content/public/browser/browser_thread.h"
-#include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/api/system_info_storage/storage_info_provider.h"
 
 namespace extensions {
 
 using api::experimental_system_info_storage::StorageInfo;
 using api::experimental_system_info_storage::StorageUnitInfo;
-using content::BrowserThread;
 
 SystemInfoStorageGetFunction::SystemInfoStorageGetFunction() {
 }
@@ -26,67 +17,19 @@ SystemInfoStorageGetFunction::~SystemInfoStorageGetFunction() {
 }
 
 bool SystemInfoStorageGetFunction::RunImpl() {
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
-      base::Bind(&SystemInfoStorageGetFunction::WorkOnFileThread, this));
+  StorageInfoProvider::Get()->StartQueryInfo(
+      base::Bind(&SystemInfoStorageGetFunction::OnGetStorageInfoCompleted,
+                 this));
   return true;
 }
 
-void SystemInfoStorageGetFunction::WorkOnFileThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-  bool success = false;
-  scoped_ptr<StorageInfoProvider> provider(StorageInfoProvider::Create());
-  StorageInfo info;
-  if (provider.get() && provider->GetStorageInfo(&info)) {
+void SystemInfoStorageGetFunction::OnGetStorageInfoCompleted(
+    const StorageInfo& info, bool success) {
+  if (success)
     SetResult(info.ToValue().release());
-    success = true;
-  } else {
-    SetError("Error in querying storage information");
-  }
-
-  // Return the result on UI thread.
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(&SystemInfoStorageGetFunction::RespondOnUIThread,
-      this, success));
-}
-
-void SystemInfoStorageGetFunction::RespondOnUIThread(bool success) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  else
+    SetError("Error occurred when querying storage information.");
   SendResponse(success);
 }
 
-#if !defined(OS_WIN)
-// A Mock implementation for temporary usage. Will be moved out for testing
-// once the platform specifc implementations are ready.
-const char kStorageTypeUnknownStr[] = "unknown";
-const char kStorageTypeHardDiskStr[] = "harddisk";
-const char kStorageTypeUSBStr[] = "usb";
-const char kStorageTypeMMCStr[] = "mmc";
-
-class MockStorageInfoProvider : public StorageInfoProvider {
- public:
-  MockStorageInfoProvider() {}
-  virtual ~MockStorageInfoProvider() {}
-  virtual bool GetStorageInfo(StorageInfo* info) OVERRIDE;
-};
-
-bool MockStorageInfoProvider::GetStorageInfo(StorageInfo* info) {
-  if (info == NULL) return false;
-  linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
-  unit->id = "0xbeaf";
-  unit->type = kStorageTypeUnknownStr;
-  unit->capacity = 4098;
-  unit->available_capacity = 1000;
-
-  info->units.push_back(unit);
-  return true;
-}
-
-// static
-StorageInfoProvider* StorageInfoProvider::Create() {
-  return new MockStorageInfoProvider();
-}
-#endif  // !OS_WIN
-
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.h b/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.h
index f925f17..eb9ccaa 100644
--- a/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.h
+++ b/chrome/browser/extensions/api/system_info_storage/system_info_storage_api.h
@@ -5,6 +5,7 @@
 #define CHROME_BROWSER_EXTENSIONS_API_SYSTEM_INFO_STORAGE_SYSTEM_INFO_STORAGE_API_H_
 
 #include "chrome/browser/extensions/extension_function.h"
+#include "chrome/common/extensions/api/experimental_system_info_storage.h"
 
 namespace extensions {
 
@@ -13,20 +14,15 @@ namespace extensions {
 class SystemInfoStorageGetFunction : public AsyncExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.systemInfo.storage.get");
-
   SystemInfoStorageGetFunction();
 
  private:
   virtual ~SystemInfoStorageGetFunction();
-
-  // AsyncExtensionFunction implementation.
   virtual bool RunImpl() OVERRIDE;
 
-  // Called on FILE thread to get storage information
-  void WorkOnFileThread();
-
-  // Responds the result back to UI thread
-  void RespondOnUIThread(bool success);
+  void OnGetStorageInfoCompleted(
+      const api::experimental_system_info_storage::StorageInfo& info,
+      bool success);
 };
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc b/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
index c55d0ae..9d46706 100644
--- a/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
+++ b/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
@@ -2,22 +2,62 @@
 // 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_storage/storage_info_provider.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/common/chrome_switches.h"
 
 namespace extensions {
 
+using api::experimental_system_info_storage::StorageInfo;
+using api::experimental_system_info_storage::StorageUnitInfo;
+
+class MockStorageInfoProvider : public StorageInfoProvider {
+ public:
+  MockStorageInfoProvider() {}
+  virtual ~MockStorageInfoProvider() {}
+
+  virtual bool QueryInfo(StorageInfo* info) OVERRIDE {
+    info->units.clear();
+
+    linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
+    unit->id = "0xbeaf";
+    unit->type = systeminfo::kStorageTypeUnknown;
+    unit->capacity = 4098;
+    unit->available_capacity = 1024;
+
+    info->units.push_back(unit);
+    return true;
+  }
+
+  virtual bool QueryUnitInfo(const std::string& id,
+                             StorageUnitInfo* info) OVERRIDE {
+    return false;
+  }
+};
+
 class SystemInfoStorageApiTest: public ExtensionApiTest {
  public:
   SystemInfoStorageApiTest() {}
   ~SystemInfoStorageApiTest() {}
+
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     ExtensionApiTest::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kEnableExperimentalExtensionApis);
   }
+
+  virtual void SetUpInProcessBrowserTestFixture() {
+    ExtensionApiTest::SetUpInProcessBrowserTestFixture();
+    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+  }
+
+ private:
+  scoped_ptr<MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoStorageApiTest, Storage) {
+  StorageInfoProvider* provider = new MockStorageInfoProvider();
+  StorageInfoProvider::InitializeForTesting(provider);
   ASSERT_TRUE(RunExtensionTest("systeminfo/storage")) << message_;
 }
 
diff --git a/chrome/browser/extensions/system_info_provider.h b/chrome/browser/extensions/system_info_provider.h
index 38fac9e..d9057d5 100644
--- a/chrome/browser/extensions/system_info_provider.h
+++ b/chrome/browser/extensions/system_info_provider.h
@@ -47,10 +47,6 @@ class SystemInfoProvider {
 
   virtual ~SystemInfoProvider() {}
 
-  // Static method to get the single shared instance. Should be implemented
-  // in the impl file for each kind of provider.
-  static SystemInfoProvider<T>* Get();
-
   // For testing
   static void InitializeForTesting(SystemInfoProvider<T>* provider) {
     DCHECK(provider != NULL);
@@ -113,12 +109,12 @@ class SystemInfoProvider {
   // Template function for creating the single shared provider instance.
   // Template paramter I is the type of SystemInfoProvider implementation.
   template<class I>
-  static SystemInfoProvider<T>* GetInstance() {
+  static I* GetInstance() {
     if (!single_shared_provider_.Get().get()) {
       I* impl = new I();
       single_shared_provider_.Get().reset(impl);
     }
-    return single_shared_provider_.Get().get();
+    return static_cast<I*>(single_shared_provider_.Get().get());
   }
 
   // The latest information filled up by QueryInfo implementation. Here we
diff --git a/chrome/chrome_browser_extensions.gypi b/chrome/chrome_browser_extensions.gypi
index 2beaed8..efa226c 100644
--- a/chrome/chrome_browser_extensions.gypi
+++ b/chrome/chrome_browser_extensions.gypi
@@ -250,6 +250,8 @@
         'browser/extensions/api/system_info_storage/system_info_storage_api.h',
         'browser/extensions/api/system_info_storage/storage_info_provider.cc',
         'browser/extensions/api/system_info_storage/storage_info_provider.h',
+        'browser/extensions/api/system_info_storage/storage_info_provider_linux.cc',
+        'browser/extensions/api/system_info_storage/storage_info_provider_mac.cc',
         'browser/extensions/api/system_info_storage/storage_info_provider_win.cc',
         'browser/extensions/api/tabs/execute_code_in_tab_function.cc',
         'browser/extensions/api/tabs/execute_code_in_tab_function.h',
diff --git a/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js b/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
index 5b4f834..787ca40 100644
--- a/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
+++ b/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
@@ -9,8 +9,12 @@ chrome.systemInfo = chrome.experimental.systemInfo;
 chrome.test.runTests([
   function testGet() {
     chrome.systemInfo.storage.get(chrome.test.callbackPass(function(info) {
-      // TODO(hmin): Need to check the value from Mock implementation
-      chrome.test.assertTrue(info.units.length > 0);
+      chrome.test.assertTrue(info.units.length == 1);
+      var unit = info.units[0];
+      chrome.test.assertTrue(unit.id == "0xbeaf");
+      chrome.test.assertTrue(unit.type == "unknown");
+      chrome.test.assertTrue(unit.capacity == 4098);
+      chrome.test.assertTrue(unit.availableCapacity == 1024);
     }));
   }
 ]);