Change unique_ptr::reset() for std::move

BUG=644626

Review-Url: https://codereview.chromium.org/2330543002
Cr-Commit-Position: refs/heads/master@{#418616}

diff --git a/media/gpu/vp9_decoder.cc b/media/gpu/vp9_decoder.cc
index a6f40d9e..b24f2466 100644
--- a/media/gpu/vp9_decoder.cc
+++ b/media/gpu/vp9_decoder.cc

@@ -59,7 +59,7 @@
       Vp9Parser::Result res = parser_.ParseNextFrame(hdr.get());
       switch (res) {
         case Vp9Parser::kOk:
-          curr_frame_hdr_.reset(hdr.release());
+          curr_frame_hdr_ = std::move(hdr);
           break;
 
         case Vp9Parser::kEOStream: