[DevTools] Add power profiler and power overview in timeline panel.

Source/devtools/front_end/SettingsScreen.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 683 matching lines @@
         message.textContent = WebInspector.UIString("These experiments could be dangerous and may require restart.");
         return subsection;
     },
 
     _createExperimentCheckbox: function(experiment)
     {
         var input = document.createElement("input");
         input.type = "checkbox";
         input.name = experiment.name;
         input.checked = experiment.isEnabled();
+
+        if (experiment.name === "powerProfile") {

[pfeldman, 2014/01/09 11:38:52]

This seems wrong - generic method should not be concrete experiment-aware.

+            function powerProfileStatusCallback(event) {
+                if (event.data)
+                    return;
+                input.disabled = true;
+                experiment.setEnabled(false);
+            }
+            WebInspector.powerProfiler.addEventListener(WebInspector.PowerProfiler.EventTypes.PowerProfileSupportStatus, powerProfileStatusCallback);
+            WebInspector.powerProfiler.checkStatus();

[pfeldman, 2014/01/09 11:38:52]

You should allow enabling this experiment unconditionally.

+        }
+
         function listener()
         {
             experiment.setEnabled(input.checked);
         }
         input.addEventListener("click", listener, false);
 
         var p = document.createElement("p");
         var label = document.createElement("label");
         label.appendChild(input);
         label.appendChild(document.createTextNode(WebInspector.UIString(experiment.title)));
@@ skipping 434 matching lines @@
         var columns = this.columns();
         for (var i = 0; i < columns.length; ++i) {
             var columnId = columns[i];
             var inputElement = this._addInputElements[columnId];
             inputElement.value = "";
         }
     },
 
     __proto__: WebInspector.SettingsList.prototype
 }