Reland 'media: Add "Hide players" button in about://media-internals' with fix

content/browser/resources/media/manager.js

Index: content/browser/resources/media/manager.js
diff --git a/content/browser/resources/media/manager.js b/content/browser/resources/media/manager.js
index 27f6b990eddf7568c2de03cef99694753e4f5263..983cca5e4e822c4a7257170ef5ab6cd8b7777f14 100644
--- a/content/browser/resources/media/manager.js
+++ b/content/browser/resources/media/manager.js
@@ -16,6 +16,11 @@ var Manager = (function() {
     this.players_ = {};
     this.audioComponents_ = [];
     this.clientRenderer_ = clientRenderer;
+
+    this.hidePlayersButton = document.getElementById('hide-players-button');
+    // In tests we may not have this button.
+    if (this.hidePlayersButton)
+      this.hidePlayersButton.onclick = this.hidePlayers_.bind(this);
   }
 
   Manager.prototype = {
@@ -78,6 +83,12 @@ var Manager = (function() {
       this.clientRenderer_.playerRemoved(this.players_, playerRemoved);
     },
 
+    hidePlayers_: function() {
+      util.object.forEach(this.players_, function(playerInfo, id) {
+        this.removePlayer(id);
+      }, this);
+    },
+
     updatePlayerInfoNoRecord: function(id, timestamp, key, value) {
       if (!this.players_[id]) {
         console.error('[updatePlayerInfo] Id ' + id + ' does not exist');