DevTools: introduce multitarget model listeners

Source/devtools/front_end/components/DOMBreakpointsSidebarPane.js

Index: Source/devtools/front_end/components/DOMBreakpointsSidebarPane.js
diff --git a/Source/devtools/front_end/components/DOMBreakpointsSidebarPane.js b/Source/devtools/front_end/components/DOMBreakpointsSidebarPane.js
index e6f4577540dcc1566cff5805a928e95ed37299db..d2b66293af0ec16d7e813202aa14a2b6524f535c 100644
--- a/Source/devtools/front_end/components/DOMBreakpointsSidebarPane.js
+++ b/Source/devtools/front_end/components/DOMBreakpointsSidebarPane.js
@@ -31,7 +31,6 @@
 /**
  * @constructor
  * @extends {WebInspector.NativeBreakpointsSidebarPane}
- * @implements {WebInspector.TargetManager.Observer}
  */
 WebInspector.DOMBreakpointsSidebarPane = function()
 {
@@ -54,28 +53,11 @@ WebInspector.DOMBreakpointsSidebarPane = function()
     this._contextMenuLabels[this._breakpointTypes.AttributeModified] = WebInspector.UIString(WebInspector.useLowerCaseMenuTitles() ? "Attributes modifications" : "Attributes Modifications");
     this._contextMenuLabels[this._breakpointTypes.NodeRemoved] = WebInspector.UIString(WebInspector.useLowerCaseMenuTitles() ? "Node removal" : "Node Removal");
 
-    WebInspector.targetManager.observeTargets(this);
+    WebInspector.targetManager.addModelListener(WebInspector.ResourceTreeModel, WebInspector.ResourceTreeModel.EventTypes.InspectedURLChanged, this._inspectedURLChanged, this);
+    WebInspector.targetManager.addModelListener(WebInspector.DOMModel, WebInspector.DOMModel.Events.NodeRemoved, this._nodeRemoved, this);
 }
 
 WebInspector.DOMBreakpointsSidebarPane.prototype = {
-    /**
-     * @param {!WebInspector.Target} target
-     */
-    targetAdded: function(target)
-    {
-        target.resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.InspectedURLChanged, this._inspectedURLChanged, this);
-        target.domModel.addEventListener(WebInspector.DOMModel.Events.NodeRemoved, this._nodeRemoved, this);
-    },
-
-    /**
-     * @param {!WebInspector.Target} target
-     */
-    targetRemoved: function(target)
-    {
-        target.resourceTreeModel.removeEventListener(WebInspector.ResourceTreeModel.EventTypes.InspectedURLChanged, this._inspectedURLChanged, this);
-        target.domModel.removeEventListener(WebInspector.DOMModel.Events.NodeRemoved, this._nodeRemoved, this);
-    },
-
     _inspectedURLChanged: function(event)
     {
         this._breakpointElements = {};