Presentation API: add UMA.

Source/modules/presentation/PresentationSession.idl

 // Copyright 2014 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.
 
 // https://w3c.github.io/presentation-api/#interface-presentationsession
 
 enum PresentationSessionState {
     "connected",
     "disconnected"
 };
 
 [
     GarbageCollected,
     RuntimeEnabled=Presentation
 ] interface PresentationSession : EventTarget {
     readonly attribute DOMString? id;
     readonly attribute PresentationSessionState state;
-    void close();
+    [MeasureAs=PresentationSessionClose] void close();
     attribute EventHandler onstatechange;
 
     // Communication
     attribute BinaryType binaryType;
     attribute EventHandler onmessage;
-    [RaisesException] void send(DOMString message);
-    [RaisesException] void send(Blob data);
-    [RaisesException] void send(ArrayBuffer data);
-    [RaisesException] void send(ArrayBufferView data);
+    [RaisesException, MeasureAs=PresentationSessionSend] void send(DOMString message);
+    [RaisesException, MeasureAs=PresentationSessionSend] void send(Blob data);
+    [RaisesException, MeasureAs=PresentationSessionSend] void send(ArrayBuffer data);
+    [RaisesException, MeasureAs=PresentationSessionSend] void send(ArrayBufferView data);
 };