unique_fd is passed by value in AIDL interfaces

FileDescriptor type in AIDL was translated into const unique_fd& in C++.
Now, it is unique_fd, i.e. passed by value, to make it easier to keep it
beyond the scope of the call.

Bug: 144943748
Test: m
Change-Id: Ic6b1a4cba71c0fedb206b5ca3fb65b9944bbd69f
diff --git a/services/mediaextractor/MediaExtractorService.h b/services/mediaextractor/MediaExtractorService.h
index 1b61c4b..1b40bf9 100644
--- a/services/mediaextractor/MediaExtractorService.h
+++ b/services/mediaextractor/MediaExtractorService.h
@@ -37,7 +37,7 @@
             ::android::sp<::android::IMediaExtractor>* _aidl_return);
 
     virtual ::android::binder::Status makeIDataSource(
-            const base::unique_fd &fd,
+            base::unique_fd fd,
             int64_t offset,
             int64_t length,
             ::android::sp<::android::IDataSource>* _aidl_return);