Make ~PPB_VideoDecoder_Impl() Destroy() its decoder host for hygiene.

Review URL: https://chromiumcodereview.appspot.com/10826280

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151332 0039d316-1c4b-4281-b951-d872f2087c98

webkit/plugins/ppapi/ppb_video_decoder_impl.cc

@@ -44,6 +44,7 @@ PPB_VideoDecoder_Impl::PPB_VideoDecoder_Impl(PP_Instance instance)
 }
 
 PPB_VideoDecoder_Impl::~PPB_VideoDecoder_Impl() {
+  Destroy();
 }
 
 // Convert PP_VideoDecoder_Profile to media::VideoCodecProfile.