DevTools: remove old Timeline front-end implementation

Source/devtools/front_end/sdk/Target.js

Index: Source/devtools/front_end/sdk/Target.js
diff --git a/Source/devtools/front_end/sdk/Target.js b/Source/devtools/front_end/sdk/Target.js
index 2a698784ae16172771ab743663904d8dcedc35d0..0551ea336520e63ae5792967f95e05f8821d6155 100644
--- a/Source/devtools/front_end/sdk/Target.js
+++ b/Source/devtools/front_end/sdk/Target.js
@@ -29,8 +29,7 @@ WebInspector.Target = function(name, connection, callback)
     if (Runtime.experiments.isEnabled("timelinePowerProfiler"))
         this.powerAgent().canProfilePower(this._initializeCapability.bind(this, WebInspector.Target.Capabilities.CanProfilePower, null));
     this.workerAgent().canInspectWorkers(this._initializeCapability.bind(this, WebInspector.Target.Capabilities.CanInspectWorkers, this._loadedWithCapabilities.bind(this, callback)));
-    if (Runtime.experiments.isEnabled("timelineOnTraceEvents"))
-        this.consoleAgent().setTracingBasedTimeline(true);
+    this.consoleAgent().setTracingBasedTimeline(true);
 }
 
 /**
@@ -160,9 +159,6 @@ WebInspector.Target.prototype = {
         if (this.hasCapability(WebInspector.Target.Capabilities.CanProfilePower))
             WebInspector.powerProfiler = new WebInspector.PowerProfiler(this);
 
-        /** @type {!WebInspector.TimelineManager} */
-        this.timelineManager = new WebInspector.TimelineManager(this);
-
         /** @type {!WebInspector.DatabaseModel} */
         this.databaseModel = new WebInspector.DatabaseModel(this);
         if (!WebInspector.databaseModel)