use unique_ptr for codec factories

Will need guards for android (at least)

Bug: skia:
Change-Id: I2bb8e656997984489ef1f2e41cd3d301c4e7b947
Reviewed-on: https://skia-review.googlesource.com/26040
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/src/codec/SkStreamBuffer.h b/src/codec/SkStreamBuffer.h
index 2b60775..7543e32 100644
--- a/src/codec/SkStreamBuffer.h
+++ b/src/codec/SkStreamBuffer.h
@@ -24,9 +24,7 @@
  */
 class SkStreamBuffer : SkNoncopyable {
 public:
-    // Takes ownership of the SkStream.
-    SkStreamBuffer(SkStream*);
-
+    SkStreamBuffer(std::unique_ptr<SkStream>);
     ~SkStreamBuffer();
 
     /**