[phantom_shim] implement deprecated frame switching api

phantom_shim/WebPage.js

@@ -91,6 +91,35 @@ class WebPage {
     this.onConsoleMessage(text);
   }
 
+  /**
+   * @return {string}
+   */
+  currentFrameName() {
+    return this.frameName;
+  }
+
+  /**
+   * @return {number}
+   */
+  childFramesCount() {
+    return this.framesCount;
+  }
+
+  /**
+   * @return {!Array<string>}
+   */
+  childFramesName() {
+    return this.framesName;
+  }
+
+  /**
+   * @param {(string|number)} frameName
+   * @return {boolean}
+   */
+  switchToChildFrame(frame) {
+    return this.switchToFrame(frame);
+  }
+
   /**
    * @return {string}
    */

third_party/phantomjs/test/module/webpage/frame-switching-deprecated.js

@@ -1,4 +1,3 @@
-//! unsupported
 async_test(function () {
     var p = require("webpage").create();