Factor telemetry to separate module

Also use exclusively in `properties-mixin`

lib/mixins/element-mixin.html

@@ -466,7 +466,6 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
        * @suppress {invalidCasts}
        */
       _initializeProperties() {
-        Polymer.telemetry.instanceCount++;
         this.constructor.finalize();
         // note: finalize template when we have access to `localName` to
         // avoid dependence on `is` for polyfilling styling.

lib/mixins/properties-mixin.html

@@ -9,6 +9,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 -->
 
 <link rel="import" href="../utils/boot.html">
+<link rel="import" href="../utils/telemetry.html">
 <link rel="import" href="../utils/mixin.html">
 <link rel="import" href="../mixins/properties-changed.html">
 
@@ -192,6 +193,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
        * @return {void}
        */
       _initializeProperties() {
+        Polymer.telemetry.instanceCount++;
         this.constructor.finalize();
         super._initializeProperties();
       }

lib/utils/boot.html

@@ -61,52 +61,5 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
   };
   /* eslint-enable */
 
-  /**
-   * Provides basic tracking of element definitions (registrations) and
-   * instance counts.
-   *
-   * @namespace
-   * @summary Provides basic tracking of element definitions (registrations) and
-   * instance counts.
-   */
-  Polymer.telemetry = {
-    /**
-     * Total number of Polymer element instances created.
-     * @type {number}
-     */
-    instanceCount: 0,
-    /**
-     * Array of Polymer element classes that have been finalized.
-     * @type {Array<Polymer.Element>}
-     */
-    registrations: [],
-    /**
-     * @param {!PolymerElementConstructor} prototype Element prototype to log
-     * @this {this}
-     * @private
-     */
-    _regLog: function(prototype) {
-      console.log('[' + prototype.is + ']: registered');
-    },
-    /**
-     * Registers a class prototype for telemetry purposes.
-     * @param {HTMLElement} prototype Element prototype to register
-     * @this {this}
-     * @protected
-     */
-    register: function(prototype) {
-      this.registrations.push(prototype);
-      Polymer.log && this._regLog(prototype);
-    },
-    /**
-     * Logs all elements registered with an `is` to the console.
-     * @public
-     * @this {this}
-     */
-    dumpRegistrations: function() {
-      this.registrations.forEach(this._regLog);
-    }
-  };
-
 })();
 </script>

lib/utils/telemetry.html

@@ -0,0 +1,63 @@
+<!--
+@license
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+<link rel="import" href="boot.html">
+<script>
+(function() {
+  'use strict';
+
+  /**
+   * Provides basic tracking of element definitions (registrations) and
+   * instance counts.
+   *
+   * @namespace
+   * @summary Provides basic tracking of element definitions (registrations) and
+   * instance counts.
+   */
+  Polymer.telemetry = {
+    /**
+     * Total number of Polymer element instances created.
+     * @type {number}
+     */
+    instanceCount: 0,
+    /**
+     * Array of Polymer element classes that have been finalized.
+     * @type {Array<Polymer.Element>}
+     */
+    registrations: [],
+    /**
+     * @param {!PolymerElementConstructor} prototype Element prototype to log
+     * @this {this}
+     * @private
+     */
+    _regLog: function(prototype) {
+      console.log('[' + prototype.is + ']: registered');
+    },
+    /**
+     * Registers a class prototype for telemetry purposes.
+     * @param {HTMLElement} prototype Element prototype to register
+     * @this {this}
+     * @protected
+     */
+    register: function(prototype) {
+      this.registrations.push(prototype);
+      Polymer.log && this._regLog(prototype);
+    },
+    /**
+     * Logs all elements registered with an `is` to the console.
+     * @public
+     * @this {this}
+     */
+    dumpRegistrations: function() {
+      this.registrations.forEach(this._regLog);
+    }
+  };
+
+})();
+</script>