[DevTools] Make toolbar counters declarative.

Source/devtools/front_end/main/AdvancedApp.js

Index: Source/devtools/front_end/main/AdvancedApp.js
diff --git a/Source/devtools/front_end/main/AdvancedApp.js b/Source/devtools/front_end/main/AdvancedApp.js
index 30aee9156f90f269dd764102d65748bb338a1027..8c73835ea86ec60c5f3cc88a1eef98e3a67cced1 100644
--- a/Source/devtools/front_end/main/AdvancedApp.js
+++ b/Source/devtools/front_end/main/AdvancedApp.js
@@ -163,6 +163,49 @@ WebInspector.AdvancedApp.prototype = {
 
 /**
  * @constructor
+ * @implements {WebInspector.StatusBarItem.Provider}
+ */
+WebInspector.AdvancedApp.DeviceCounter = function()
+{
+    if (!WebInspector.experimentsSettings.devicesPanel.isEnabled() || !(WebInspector.app instanceof WebInspector.AdvancedApp)) {
+        this._counter = null;
+        return;
+    }
+
+    this._counter = new WebInspector.StatusBarCounter(["device-icon-small"]);
+    this._counter.addEventListener("click", showDevices);
+
+    function showDevices()
+    {
+        WebInspector.inspectorView.showViewInDrawer("devices", true);
+    }
+
+    InspectorFrontendHost.setDeviceCountUpdatesEnabled(true);
+    InspectorFrontendHost.events.addEventListener(InspectorFrontendHostAPI.Events.DeviceCountUpdated, this._onDeviceCountUpdated, this);
+}
+
+WebInspector.AdvancedApp.DeviceCounter.prototype = {
+    /**
+     * @param {!WebInspector.Event} event
+     */
+    _onDeviceCountUpdated: function(event)
+    {
+        var count = /** @type {number} */ (event.data);
+        this._counter.setCounter("device-icon-small", count, WebInspector.UIString(count > 1 ? "%d devices found" : "%d device found", count));
+        WebInspector.inspectorView.toolbarItemResized();
+    },
+
+    /**
+     * @return {?WebInspector.StatusBarItem}
+     */
+    item: function()
+    {
+        return this._counter;
+    }
+}
+
+/**
+ * @constructor
  */
 WebInspector.Toolbox = function()
 {