Make APIUtil::DownloadFile return ScopedFile

So that adding another RemoteFileSyncServiced method like
DownloadRemoteFile() for conflicting resolution handling
becomes easier.

BUG=177159
R=nhiroki@chromium.org, tzik@chromium.org

Review URL: https://codereview.chromium.org/19487003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@213073 0039d316-1c4b-4281-b951-d872f2087c98

12 files changed, 111 insertions, 92 deletions

diff --git a/chrome/browser/sync_file_system/drive_backend/api_util.cc b/chrome/browser/sync_file_system/drive_backend/api_util.cc
index 84cb34a..e1ddfb7 100644
--- a/chrome/browser/sync_file_system/drive_backend/api_util.cc
+++ b/chrome/browser/sync_file_system/drive_backend/api_util.cc
@@ -9,6 +9,7 @@
 #include <sstream>
 #include <string>
 
+#include "base/file_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
@@ -137,9 +138,24 @@ std::string GetMimeTypeFromTitle(const std::string& title) {
   return mime_type;
 }
 
+bool CreateTemporaryFile(const base::FilePath& dir_path,
+                         webkit_blob::ScopedFile* temp_file) {
+  base::FilePath temp_file_path;
+  const bool success = file_util::CreateDirectory(dir_path) &&
+      file_util::CreateTemporaryFileInDir(dir_path, &temp_file_path);
+  if (!success)
+    return success;
+  *temp_file =
+      webkit_blob::ScopedFile(temp_file_path,
+                              webkit_blob::ScopedFile::DELETE_ON_SCOPE_OUT,
+                              base::MessageLoopProxy::current().get());
+  return success;
+}
+
 }  // namespace
 
-APIUtil::APIUtil(Profile* profile)
+APIUtil::APIUtil(Profile* profile,
+                 const base::FilePath& temp_dir_path)
     : wapi_url_generator_(
           GURL(google_apis::GDataWapiUrlGenerator::kBaseUrlForProduction),
           GURL(google_apis::GDataWapiUrlGenerator::
@@ -148,7 +164,8 @@ APIUtil::APIUtil(Profile* profile)
           GURL(google_apis::DriveApiUrlGenerator::kBaseUrlForProduction),
           GURL(google_apis::DriveApiUrlGenerator::
                kBaseDownloadUrlForProduction)),
-      upload_next_key_(0) {
+      upload_next_key_(0),
+      temp_dir_path_(temp_dir_path) {
   if (IsDriveAPIDisabled()) {
     drive_service_.reset(new drive::GDataWapiService(
         profile->GetRequestContext(),
@@ -175,10 +192,12 @@ APIUtil::APIUtil(Profile* profile)
 
 scoped_ptr<APIUtil> APIUtil::CreateForTesting(
     Profile* profile,
+    const base::FilePath& temp_dir_path,
     scoped_ptr<drive::DriveServiceInterface> drive_service,
     scoped_ptr<drive::DriveUploaderInterface> drive_uploader) {
   return make_scoped_ptr(new APIUtil(
       profile,
+      temp_dir_path,
       GURL(kFakeServerBaseUrl),
       GURL(kFakeDownloadServerBaseUrl),
       drive_service.Pass(),
@@ -186,13 +205,15 @@ scoped_ptr<APIUtil> APIUtil::CreateForTesting(
 }
 
 APIUtil::APIUtil(Profile* profile,
+                 const base::FilePath& temp_dir_path,
                  const GURL& base_url,
                  const GURL& base_download_url,
                  scoped_ptr<drive::DriveServiceInterface> drive_service,
                  scoped_ptr<drive::DriveUploaderInterface> drive_uploader)
     : wapi_url_generator_(base_url, base_download_url),
       drive_api_url_generator_(base_url, base_download_url),
-      upload_next_key_(0) {
+      upload_next_key_(0),
+      temp_dir_path_(temp_dir_path) {
   drive_service_ = drive_service.Pass();
   drive_service_->Initialize(profile);
   drive_service_->AddObserver(this);
@@ -484,20 +505,19 @@ void APIUtil::ContinueListing(const GURL& feed_url,
 
 void APIUtil::DownloadFile(const std::string& resource_id,
                            const std::string& local_file_md5,
-                           const base::FilePath& local_file_path,
                            const DownloadFileCallback& callback) {
   DCHECK(CalledOnValidThread());
+  DCHECK(!temp_dir_path_.empty());
   DVLOG(2) << "Downloading file [" << resource_id << "]";
 
-  drive_service_->GetResourceEntry(
-      resource_id,
-      base::Bind(&APIUtil::DidGetResourceEntry,
-                 AsWeakPtr(),
-                 base::Bind(&APIUtil::DownloadFileInternal,
-                            AsWeakPtr(),
-                            local_file_md5,
-                            local_file_path,
-                            callback)));
+  scoped_ptr<webkit_blob::ScopedFile> temp_file(new webkit_blob::ScopedFile);
+  webkit_blob::ScopedFile* temp_file_ptr = temp_file.get();
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::FILE, FROM_HERE,
+      base::Bind(&CreateTemporaryFile, temp_dir_path_, temp_file_ptr),
+      base::Bind(&APIUtil::DidGetTemporaryFileForDownload,
+                 AsWeakPtr(), resource_id, local_file_md5,
+                 base::Passed(&temp_file), callback));
 }
 
 void APIUtil::UploadNewFile(const std::string& directory_resource_id,
@@ -699,9 +719,33 @@ void APIUtil::DidGetResourceEntry(
   callback.Run(error, entry.Pass());
 }
 
+void APIUtil::DidGetTemporaryFileForDownload(
+    const std::string& resource_id,
+    const std::string& local_file_md5,
+    scoped_ptr<webkit_blob::ScopedFile> local_file,
+    const DownloadFileCallback& callback,
+    bool success) {
+  if (!success) {
+    DVLOG(2) << "Error in creating a temp file under "
+             << temp_dir_path_.value();
+    callback.Run(google_apis::GDATA_FILE_ERROR, std::string(), 0, base::Time(),
+                 local_file.Pass());
+    return;
+  }
+  drive_service_->GetResourceEntry(
+      resource_id,
+      base::Bind(&APIUtil::DidGetResourceEntry,
+                 AsWeakPtr(),
+                 base::Bind(&APIUtil::DownloadFileInternal,
+                            AsWeakPtr(),
+                            local_file_md5,
+                            base::Passed(&local_file),
+                            callback)));
+}
+
 void APIUtil::DownloadFileInternal(
     const std::string& local_file_md5,
-    const base::FilePath& local_file_path,
+    scoped_ptr<webkit_blob::ScopedFile> local_file,
     const DownloadFileCallback& callback,
     google_apis::GDataErrorCode error,
     scoped_ptr<google_apis::ResourceEntry> entry) {
@@ -709,7 +753,8 @@ void APIUtil::DownloadFileInternal(
 
   if (error != google_apis::HTTP_SUCCESS) {
     DVLOG(2) << "Error on getting resource entry for download";
-    callback.Run(error, std::string(), 0, base::Time());
+    callback.Run(error, std::string(), 0, base::Time(),
+                 local_file.Pass());
     return;
   }
   DCHECK(entry);
@@ -720,23 +765,27 @@ void APIUtil::DownloadFileInternal(
     callback.Run(google_apis::HTTP_NOT_MODIFIED,
                  local_file_md5,
                  entry->file_size(),
-                 entry->updated_time());
+                 entry->updated_time(),
+                 local_file.Pass());
     return;
   }
 
   DVLOG(2) << "Downloading file: " << entry->resource_id();
   const std::string& resource_id = entry->resource_id();
+  const base::FilePath& local_file_path = local_file->path();
   drive_service_->DownloadFile(local_file_path,
                                resource_id,
                                base::Bind(&APIUtil::DidDownloadFile,
                                           AsWeakPtr(),
                                           base::Passed(&entry),
+                                          base::Passed(&local_file),
                                           callback),
                                google_apis::GetContentCallback(),
                                google_apis::ProgressCallback());
 }
 
 void APIUtil::DidDownloadFile(scoped_ptr<google_apis::ResourceEntry> entry,
+                              scoped_ptr<webkit_blob::ScopedFile> local_file,
                               const DownloadFileCallback& callback,
                               google_apis::GDataErrorCode error,
                               const base::FilePath& downloaded_file_path) {
@@ -747,7 +796,8 @@ void APIUtil::DidDownloadFile(scoped_ptr<google_apis::ResourceEntry> entry,
     DVLOG(2) << "Error on downloading file: " << error;
 
   callback.Run(
-      error, entry->file_md5(), entry->file_size(), entry->updated_time());
+      error, entry->file_md5(), entry->file_size(), entry->updated_time(),
+      local_file.Pass());
 }
 
 void APIUtil::DidUploadNewFile(const std::string& parent_resource_id,
diff --git a/chrome/browser/sync_file_system/drive_backend/api_util.h b/chrome/browser/sync_file_system/drive_backend/api_util.h
index 8c17628..e976a15 100644
--- a/chrome/browser/sync_file_system/drive_backend/api_util.h
+++ b/chrome/browser/sync_file_system/drive_backend/api_util.h
@@ -15,6 +15,7 @@
 #include "chrome/browser/google_apis/gdata_wapi_url_generator.h"
 #include "chrome/browser/sync_file_system/drive_backend/api_util_interface.h"
 #include "net/base/network_change_notifier.h"
+#include "webkit/common/blob/scoped_file.h"
 
 class GURL;
 class Profile;
@@ -44,7 +45,7 @@ class APIUtil : public APIUtilInterface,
                               scoped_ptr<google_apis::ResourceEntry> entry)>
       EnsureUniquenessCallback;
 
-  explicit APIUtil(Profile* profile);
+  APIUtil(Profile* profile, const base::FilePath& temp_dir_path);
   virtual ~APIUtil();
 
   virtual void AddObserver(APIUtilObserver* observer) OVERRIDE;
@@ -52,6 +53,7 @@ class APIUtil : public APIUtilInterface,
 
   static scoped_ptr<APIUtil> CreateForTesting(
       Profile* profile,
+      const base::FilePath& temp_dir_path,
       scoped_ptr<drive::DriveServiceInterface> drive_service,
       scoped_ptr<drive::DriveUploaderInterface> drive_uploader);
 
@@ -74,7 +76,6 @@ class APIUtil : public APIUtilInterface,
                                const ResourceListCallback& callback) OVERRIDE;
   virtual void DownloadFile(const std::string& resource_id,
                             const std::string& local_file_md5,
-                            const base::FilePath& local_file_path,
                             const DownloadFileCallback& callback) OVERRIDE;
   virtual void UploadNewFile(const std::string& directory_resource_id,
                              const base::FilePath& local_file_path,
@@ -115,6 +116,7 @@ class APIUtil : public APIUtilInterface,
 
   // Constructor for test use.
   APIUtil(Profile* profile,
+          const base::FilePath& temp_dir_path,
           const GURL& base_url,
           const GURL& base_download_url,
           scoped_ptr<drive::DriveServiceInterface> drive_service,
@@ -169,13 +171,21 @@ class APIUtil : public APIUtilInterface,
                            google_apis::GDataErrorCode error,
                            scoped_ptr<google_apis::ResourceEntry> entry);
 
+  void DidGetTemporaryFileForDownload(
+      const std::string& resource_id,
+      const std::string& local_file_md5,
+      scoped_ptr<webkit_blob::ScopedFile> local_file,
+      const DownloadFileCallback& callback,
+      bool success);
+
   void DownloadFileInternal(const std::string& local_file_md5,
-                            const base::FilePath& local_file_path,
+                            scoped_ptr<webkit_blob::ScopedFile> local_file,
                             const DownloadFileCallback& callback,
                             google_apis::GDataErrorCode error,
                             scoped_ptr<google_apis::ResourceEntry> entry);
 
   void DidDownloadFile(scoped_ptr<google_apis::ResourceEntry> entry,
+                       scoped_ptr<webkit_blob::ScopedFile> local_file,
                        const DownloadFileCallback& callback,
                        google_apis::GDataErrorCode error,
                        const base::FilePath& downloaded_file_path);
@@ -243,6 +253,8 @@ class APIUtil : public APIUtilInterface,
   UploadCallbackMap upload_callback_map_;
   UploadKey upload_next_key_;
 
+  base::FilePath temp_dir_path_;
+
   std::string root_resource_id_;
 
   ObserverList<APIUtilObserver> observers_;
diff --git a/chrome/browser/sync_file_system/drive_backend/api_util_interface.h b/chrome/browser/sync_file_system/drive_backend/api_util_interface.h
index 46867f2..e4a2ca7 100644
--- a/chrome/browser/sync_file_system/drive_backend/api_util_interface.h
+++ b/chrome/browser/sync_file_system/drive_backend/api_util_interface.h
@@ -22,6 +22,10 @@ namespace google_apis {
 class DriveUploaderInterface;
 }
 
+namespace webkit_blob {
+class ScopedFile;
+}
+
 namespace sync_file_system {
 namespace drive_backend {
 
@@ -46,7 +50,8 @@ class APIUtilInterface {
   typedef base::Callback<void(google_apis::GDataErrorCode error,
                               const std::string& file_md5,
                               int64 file_size,
-                              const base::Time& last_updated)>
+                              const base::Time& last_updated,
+                              scoped_ptr<webkit_blob::ScopedFile> downloaded)>
       DownloadFileCallback;
   typedef base::Callback<void(google_apis::GDataErrorCode error,
                               const std::string& resource_id,
@@ -130,7 +135,6 @@ class APIUtilInterface {
   // empty.
   virtual void DownloadFile(const std::string& resource_id,
                             const std::string& local_file_md5,
-                            const base::FilePath& local_file_path,
                             const DownloadFileCallback& callback) = 0;
 
   // Uploads the new file |local_file_path| with specified |title| into the
diff --git a/chrome/browser/sync_file_system/drive_backend/api_util_unittest.cc b/chrome/browser/sync_file_system/drive_backend/api_util_unittest.cc
index 1407ab9..3f03963 100644
--- a/chrome/browser/sync_file_system/drive_backend/api_util_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/api_util_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/sync_file_system/drive_backend/api_util.h"
 
+#include "base/file_util.h"
 #include "base/location.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ -214,8 +215,10 @@ class APIUtilTest : public testing::Test {
     fake_drive_helper_.reset(new FakeDriveServiceHelper(
         fake_drive_service_, fake_drive_uploader_));
 
+    ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
     api_util_ = APIUtil::CreateForTesting(
         &profile_,
+        temp_dir_.path(),
         scoped_ptr<DriveServiceInterface>(fake_drive_service_),
         scoped_ptr<DriveUploaderInterface>(fake_drive_uploader_));
 
@@ -324,6 +327,7 @@ class APIUtilTest : public testing::Test {
  private:
   content::TestBrowserThreadBundle thread_bundle_;
 
+  base::ScopedTempDir temp_dir_;
   TestingProfile profile_;
   scoped_ptr<APIUtil> api_util_;
   FakeDriveServiceWrapper* fake_drive_service_;
@@ -363,8 +367,10 @@ void DidDownloadFile(Output* output,
                      GDataErrorCode error,
                      const std::string& file_md5,
                      int64 file_size,
-                     const base::Time& updated_time) {
+                     const base::Time& updated_time,
+                     scoped_ptr<webkit_blob::ScopedFile> file) {
   ASSERT_TRUE(output);
+  ASSERT_TRUE(base::PathExists(file->path()));
   output->error = error;
   output->file_md5 = file_md5;
 }
@@ -585,15 +591,10 @@ void APIUtilTest::TestDownloadFile() {
   scoped_ptr<ResourceEntry> file;
   SetUpFile(origin_root_id, kFileContent, kFileTitle, &file);
 
-  base::ScopedTempDir temp_dir;
-  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
-  base::FilePath output_file_path = temp_dir.path().AppendASCII(file->title());
-
   Output output;
   api_util()->DownloadFile(
       file->resource_id(),
       "",  // local_file_md5
-      output_file_path,
       base::Bind(&DidDownloadFile, &output));
   base::MessageLoop::current()->RunUntilIdle();
 
@@ -610,17 +611,12 @@ void APIUtilTest::TestDownloadFileInNotModified() {
   scoped_ptr<ResourceEntry> file;
   SetUpFile(origin_root_id, kFileContent, kFileTitle, &file);
 
-  base::ScopedTempDir temp_dir;
-  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
-  base::FilePath output_file_path = temp_dir.path().AppendASCII(file->title());
-
   // Since local file's hash value is equal to remote file's one, it is expected
   // to cancel download the file and to return NOT_MODIFIED status code.
   Output output;
   api_util()->DownloadFile(
       file->resource_id(),
       file->file_md5(),
-      output_file_path,
       base::Bind(&DidDownloadFile, &output));
   base::MessageLoop::current()->RunUntilIdle();
 
diff --git a/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service.cc b/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service.cc
index 4ff04d8..9e07bdd 100644
--- a/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service.cc
@@ -58,20 +58,6 @@ const base::FilePath::CharType* GetSyncFileSystemDir() {
       ? kSyncFileSystemDirDev : kSyncFileSystemDir;
 }
 
-bool CreateTemporaryFile(const base::FilePath& dir_path,
-                         webkit_blob::ScopedFile* temp_file) {
-  base::FilePath temp_file_path;
-  const bool success = file_util::CreateDirectory(dir_path) &&
-      file_util::CreateTemporaryFileInDir(dir_path, &temp_file_path);
-  if (!success)
-    return success;
-  *temp_file =
-      webkit_blob::ScopedFile(temp_file_path,
-                              webkit_blob::ScopedFile::DELETE_ON_SCOPE_OUT,
-                              base::MessageLoopProxy::current().get());
-  return success;
-}
-
 void EmptyStatusCallback(SyncStatusCode status) {}
 
 }  // namespace
@@ -325,7 +311,7 @@ void DriveFileSyncService::Initialize(
   temporary_file_dir_ =
       profile_->GetPath().Append(GetSyncFileSystemDir()).Append(kTempDirName);
 
-  api_util_.reset(new drive_backend::APIUtil(profile_));
+  api_util_.reset(new drive_backend::APIUtil(profile_, temporary_file_dir_));
   api_util_->AddObserver(this);
 
   metadata_store_.reset(new DriveMetadataStore(
diff --git a/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_fake_unittest.cc b/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_fake_unittest.cc
index 2d1e8a2..6f8431a 100644
--- a/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_fake_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_fake_unittest.cc
@@ -207,6 +207,7 @@ class DriveFileSyncServiceFakeTest : public testing::Test {
 
     api_util_ = APIUtil::CreateForTesting(
         profile_.get(),
+        fake_drive_helper_->base_dir_path().AppendASCII("tmp"),
         scoped_ptr<DriveServiceInterface>(fake_drive_service_),
         scoped_ptr<DriveUploaderInterface>(drive_uploader)).Pass();
     metadata_store_.reset(new DriveMetadataStore(
diff --git a/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_sync_unittest.cc b/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_sync_unittest.cc
index 8d273d1..41e9037 100644
--- a/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_sync_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/drive_file_sync_service_sync_unittest.cc
@@ -118,6 +118,7 @@ class DriveFileSyncServiceSyncTest : public testing::Test {
 
     scoped_ptr<APIUtil> api_util(APIUtil::CreateForTesting(
         &profile_,
+        fake_drive_helper_->base_dir_path().AppendASCII("tmp"),
         scoped_ptr<drive::DriveServiceInterface>(fake_drive_service_),
         scoped_ptr<drive::DriveUploaderInterface>(drive_uploader_)));
 
diff --git a/chrome/browser/sync_file_system/drive_backend/fake_api_util.cc b/chrome/browser/sync_file_system/drive_backend/fake_api_util.cc
index c8e01a1..88ce414 100644
--- a/chrome/browser/sync_file_system/drive_backend/fake_api_util.cc
+++ b/chrome/browser/sync_file_system/drive_backend/fake_api_util.cc
@@ -10,6 +10,7 @@
 #include "base/location.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "chrome/browser/google_apis/drive_entry_kinds.h"
+#include "webkit/common/blob/scoped_file.h"
 
 namespace sync_file_system {
 namespace drive_backend {
@@ -145,7 +146,6 @@ void FakeAPIUtil::ContinueListing(const GURL& feed_url,
 
 void FakeAPIUtil::DownloadFile(const std::string& resource_id,
                                const std::string& local_file_md5,
-                               const base::FilePath& local_file_path,
                                const DownloadFileCallback& callback) {
   RemoteResourceByResourceId::iterator found =
       remote_resources_.find(resource_id);
@@ -163,9 +163,12 @@ void FakeAPIUtil::DownloadFile(const std::string& resource_id,
     error = google_apis::HTTP_SUCCESS;
   }
 
+  scoped_ptr<webkit_blob::ScopedFile> dummy_local_file(
+      new webkit_blob::ScopedFile);
   base::MessageLoopProxy::current()->PostTask(
       FROM_HERE,
-      base::Bind(callback, error, file_md5, file_size, updated_time));
+      base::Bind(callback, error, file_md5, file_size, updated_time,
+                 base::Passed(&dummy_local_file)));
 }
 
 void FakeAPIUtil::UploadNewFile(const std::string& directory_resource_id,
diff --git a/chrome/browser/sync_file_system/drive_backend/fake_api_util.h b/chrome/browser/sync_file_system/drive_backend/fake_api_util.h
index 52c201e..3c5a552 100644
--- a/chrome/browser/sync_file_system/drive_backend/fake_api_util.h
+++ b/chrome/browser/sync_file_system/drive_backend/fake_api_util.h
@@ -79,7 +79,6 @@ class FakeAPIUtil : public APIUtilInterface {
                                const ResourceListCallback& callback) OVERRIDE;
   virtual void DownloadFile(const std::string& resource_id,
                             const std::string& local_file_md5,
-                            const base::FilePath& local_file_path,
                             const DownloadFileCallback& callback) OVERRIDE;
   virtual void UploadNewFile(const std::string& directory_resource_id,
                              const base::FilePath& local_file_path,
diff --git a/chrome/browser/sync_file_system/drive_backend/fake_api_util_unittest.cc b/chrome/browser/sync_file_system/drive_backend/fake_api_util_unittest.cc
index 88a7ede..a0239cd 100644
--- a/chrome/browser/sync_file_system/drive_backend/fake_api_util_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/fake_api_util_unittest.cc
@@ -11,6 +11,7 @@
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/google_apis/gdata_errorcode.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "webkit/common/blob/scoped_file.h"
 
 namespace sync_file_system {
 namespace drive_backend {
@@ -22,7 +23,8 @@ void DidDownloadFile(google_apis::GDataErrorCode* error_out,
                      google_apis::GDataErrorCode error,
                      const std::string& file_md5,
                      int64 file_size,
-                     const base::Time& updated_time) {
+                     const base::Time& updated_time,
+                     scoped_ptr<webkit_blob::ScopedFile> downloaded_file) {
   *error_out = error;
   *file_md5_out = file_md5;
 }
@@ -55,7 +57,6 @@ TEST(FakeAPIUtilTest, ChangeSquashTest) {
   std::string kMD5_1("md5 1");
   std::string kMD5_2("md5 2");
   std::string kMD5_3("md5 3");
-  base::FilePath kTempFilePath(FILE_PATH_LITERAL("tmp_file"));
 
   api_util.PushRemoteChange(kParentResourceId,
                             kParentTitle,
@@ -97,7 +98,6 @@ TEST(FakeAPIUtilTest, ChangeSquashTest) {
   std::string md5;
   api_util.DownloadFile(kResourceId1,
                         kMD5_1,
-                        kTempFilePath,
                         base::Bind(DidDownloadFile, &error, &md5));
   message_loop.RunUntilIdle();
   EXPECT_EQ(google_apis::HTTP_NOT_FOUND, error);
diff --git a/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.cc b/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.cc
index fa1cbc9..2377974 100644
--- a/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.cc
+++ b/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.cc
@@ -15,20 +15,6 @@ using fileapi::FileSystemURL;
 
 namespace {
 
-bool CreateTemporaryFile(const base::FilePath& dir_path,
-                         webkit_blob::ScopedFile* temp_file) {
-  base::FilePath temp_file_path;
-  const bool success = file_util::CreateDirectory(dir_path) &&
-      file_util::CreateTemporaryFileInDir(dir_path, &temp_file_path);
-  if (!success)
-    return success;
-  *temp_file =
-      webkit_blob::ScopedFile(temp_file_path,
-                              webkit_blob::ScopedFile::DELETE_ON_SCOPE_OUT,
-                              base::MessageLoopProxy::current().get());
-  return success;
-}
-
 void EmptyStatusCallback(sync_file_system::SyncStatusCode status) {}
 
 }  // namespace
@@ -201,25 +187,6 @@ void RemoteSyncDelegate::DeleteMetadata(const SyncStatusCallback& callback) {
 }
 
 void RemoteSyncDelegate::DownloadFile(const SyncStatusCallback& callback) {
-  content::BrowserThread::PostTaskAndReplyWithResult(
-      content::BrowserThread::FILE, FROM_HERE,
-      base::Bind(&CreateTemporaryFile,
-                 sync_service_->temporary_file_dir_,
-                 &temporary_file_),
-      base::Bind(&RemoteSyncDelegate::DidGetTemporaryFileForDownload,
-                 AsWeakPtr(), callback));
-}
-
-void RemoteSyncDelegate::DidGetTemporaryFileForDownload(
-    const SyncStatusCallback& callback,
-    bool success) {
-  if (!success) {
-    AbortSync(callback, SYNC_FILE_ERROR_FAILED);
-    return;
-  }
-
-  DCHECK(!temporary_file_.path().empty());
-
   // We should not use the md5 in metadata for FETCH type to avoid the download
   // finishes due to NOT_MODIFIED.
   std::string md5_checksum;
@@ -229,7 +196,6 @@ void RemoteSyncDelegate::DidGetTemporaryFileForDownload(
   api_util()->DownloadFile(
       remote_change_.resource_id,
       md5_checksum,
-      temporary_file_.path(),
       base::Bind(&RemoteSyncDelegate::DidDownloadFile,
                  AsWeakPtr(),
                  callback));
@@ -240,7 +206,8 @@ void RemoteSyncDelegate::DidDownloadFile(
     google_apis::GDataErrorCode error,
     const std::string& md5_checksum,
     int64 file_size,
-    const base::Time& updated_time) {
+    const base::Time& updated_time,
+    scoped_ptr<webkit_blob::ScopedFile> downloaded_file) {
   if (error == google_apis::HTTP_NOT_MODIFIED) {
     sync_action_ = SYNC_ACTION_NONE;
     DidApplyRemoteChange(callback, SYNC_STATUS_OK);
@@ -253,6 +220,7 @@ void RemoteSyncDelegate::DidDownloadFile(
     return;
   }
 
+  temporary_file_ = downloaded_file->Pass();
   drive_metadata_.set_md5_checksum(md5_checksum);
   remote_change_processor()->ApplyRemoteChange(
       remote_file_change(), temporary_file_.path(), url(),
diff --git a/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.h b/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.h
index 5d8ccda..ff48cea 100644
--- a/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.h
+++ b/chrome/browser/sync_file_system/drive_backend/remote_sync_delegate.h
@@ -56,13 +56,12 @@ class RemoteSyncDelegate : public base::SupportsWeakPtr<RemoteSyncDelegate> {
                             SyncStatusCode status);
   void DeleteMetadata(const SyncStatusCallback& callback);
   void DownloadFile(const SyncStatusCallback& callback);
-  void DidGetTemporaryFileForDownload(const SyncStatusCallback& callback,
-                                      bool success);
   void DidDownloadFile(const SyncStatusCallback& callback,
                        google_apis::GDataErrorCode error,
                        const std::string& md5_checksum,
                        int64 file_size,
-                       const base::Time& updated_time);
+                       const base::Time& updated_time,
+                       scoped_ptr<webkit_blob::ScopedFile> downloaded_file);
   void HandleConflict(const SyncStatusCallback& callback,
                       SyncFileType remote_file_type);
   void HandleLocalWin(const SyncStatusCallback& callback);