Polish the SystemInfoProvider template code and refactor StorageInfoProvider based on it

chrome/browser/extensions/api/system_info_storage/system_info_storage_api.cc

Index: chrome/browser/extensions/api/system_info_storage/system_info_storage_api.cc
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 91916ee90d1d9f213adccfff8082e5f5d0933604..187be391f34da17b7d242e334f988248cba5090e 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