Revert of MediaPerceptionPrivate API impl and testing.

extensions/test/data/media_perception_private/media_perception/runtest.js

-// Copyright 2017 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.
-
-// Set the state to STARTED to automatically start listening to
-// MediaPerceptionDetection signals.
-
-chrome.test.runTests([
-    function setStateRunning() {
-      // Need to start the mocked media analytics process.
-      chrome.mediaPerceptionPrivate.setState({
-        status: 'RUNNING'
-      }, chrome.test.callbackPass(function(state) {
-        chrome.test.assertEq({ status: 'RUNNING' }, state);
-      }));
-    },
-    function registerListener() {
-      chrome.test.listenOnce(
-          chrome.mediaPerceptionPrivate.onMediaPerception,
-          function(evt) {
-            chrome.test.assertEq({
-              framePerceptions: [{
-                frameId: 1
-              }]
-            }, evt);
-          });
-      // By sending this message, we trigger the fake D-Bus client to fire an
-      // onMediaPerception event.
-      chrome.test.sendMessage('mediaPerceptionListenerSet');
-    }
-]);
-