Extract GetResolveFile into DownloadOperation.

chrome/browser/chromeos/drive/file_system/drive_operations.cc

Index: chrome/browser/chromeos/drive/file_system/drive_operations.cc
diff --git a/chrome/browser/chromeos/drive/file_system/drive_operations.cc b/chrome/browser/chromeos/drive/file_system/drive_operations.cc
index 9eaef46248255ba69b9187d8fccbcd6031f25ecf..64efe5f91e847fa9a92b5ae90ba279c6012d18ac 100644
--- a/chrome/browser/chromeos/drive/file_system/drive_operations.cc
+++ b/chrome/browser/chromeos/drive/file_system/drive_operations.cc
@@ -8,6 +8,7 @@
 #include "chrome/browser/chromeos/drive/file_system/copy_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/create_directory_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/create_file_operation.h"
+#include "chrome/browser/chromeos/drive/file_system/download_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/move_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/remove_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/search_operation.h"
@@ -57,6 +58,8 @@ void DriveOperations::Init(OperationObserver* observer,
       new MoveOperation(observer, scheduler, metadata));
   remove_operation_.reset(
       new RemoveOperation(observer, scheduler, metadata, cache));
+  download_operation_.reset(new DownloadOperation(
+      blocking_task_runner, observer, scheduler, metadata, cache));
   update_operation_.reset(
       new UpdateOperation(observer, scheduler, metadata, cache));
   search_operation_.reset(
@@ -134,6 +137,20 @@ void DriveOperations::Remove(const base::FilePath& file_path,
   remove_operation_->Remove(file_path, is_recursive, callback);
 }
 
+void DriveOperations::EnsureFileDownloaded(
+    const base::FilePath& file_path,
+    DriveClientContext context,
+    const GetFileContentInitializedCallback& initialized_callback,
+    const google_apis::GetContentCallback& get_content_callback,
+    const GetFileCallback& completion_callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!completion_callback.is_null());
+
+  download_operation_->EnsureFileDownloaded(
+      file_path, context, initialized_callback, get_content_callback,
+      completion_callback);
+}
+
 void DriveOperations::UpdateFileByResourceId(
     const std::string& resource_id,
     DriveClientContext context,