drive: Move temporary file removal responsiblity to FileCache

chrome/browser/chromeos/drive/file_cache.h

Index: chrome/browser/chromeos/drive/file_cache.h
diff --git a/chrome/browser/chromeos/drive/file_cache.h b/chrome/browser/chromeos/drive/file_cache.h
index 4634d870c000bc56a8ab22cbb72d413472f45756..bb3f911820275f4fdfc4c5136ae6a872b56a7164 100644
--- a/chrome/browser/chromeos/drive/file_cache.h
+++ b/chrome/browser/chromeos/drive/file_cache.h
@@ -208,13 +208,18 @@ class FileCache {
                                       FileOperationType file_operation_type,
                                       const FileOperationCallback& callback);
 
-  // Pins the specified entry.
+  // Runs Pin() on |blocking_task_runner_|, and calls |callback| with the result
+  // asynchronously.
   // |callback| must not be null.
   // Must be called on the UI thread.
   void PinOnUIThread(const std::string& resource_id,
                      const std::string& md5,
                      const FileOperationCallback& callback);
 
+  // Pins the specified entry.
+  FileError Pin(const std::string& resource_id,
+                const std::string& md5);
+
   // Runs Unpin() on |blocking_task_runner_|, and calls |callback| with the
   // result asynchronously.
   // |callback| must not be null.
@@ -303,6 +308,7 @@ class FileCache {
 
  private:
   friend class FileCacheTest;
+  friend class FileCacheTestOnUIThread;
 
   // Enum defining origin of a cached file.
   enum CachedFileOrigin {
@@ -341,10 +347,6 @@ class FileCache {
                           FileOperationType file_operation_type,
                           CachedFileOrigin origin);
 
-  // Used to implement PinOnUIThread.
-  FileError Pin(const std::string& resource_id,
-                const std::string& md5);
-
   // Used to implement MarkAsMountedOnUIThread.
   FileError MarkAsMounted(const std::string& resource_id,
                           const std::string& md5,