SkFILEStream::Make: fix leak.

Change-Id: I218ae89f049df3d05380b46ca672bb1f6fcb5ea4
Reviewed-on: https://skia-review.googlesource.com/38962
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/include/core/SkStream.h b/include/core/SkStream.h
index fde6baf..5ef8519 100644
--- a/include/core/SkStream.h
+++ b/include/core/SkStream.h
@@ -264,8 +264,8 @@
     ~SkFILEStream() override;
 
     static std::unique_ptr<SkFILEStream> Make(const char path[]) {
-        SkFILEStream* stream = new SkFILEStream(path);
-        return stream->isValid() ? std::unique_ptr<SkFILEStream>(stream) : nullptr;
+        std::unique_ptr<SkFILEStream> stream(new SkFILEStream(path));
+        return stream->isValid() ? std::move(stream) : nullptr;
     }
 
     /** Returns true if the current path could be opened. */