[Cast] Compute utilization metrics and add performance overlay.

media/cast/sender/sender_encoded_frame.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/cast/sender/sender_encoded_frame.h"
+
+namespace media {
+namespace cast {
+
+SenderEncodedFrame::SenderEncodedFrame()
+    : EncodedFrame(),
+      deadline_utilization(-1.0),
+      lossy_utilization(-1.0) {}
+
+SenderEncodedFrame::~SenderEncodedFrame() {}
+
+}  //  namespace cast
+}  //  namespace media