code: function instrumentMemoryClicked() {
    _gaq.push(['_trackEvent', 'popup', 'instrument_memory']);
  
    try {
      new Function('return %GetHeapUsage()');
    } catch (e) {
      // Pop open docs page.
      port.postMessage({
        command: 'instrument',
        type: 'memory',
        needsHelp: true
      });
      return;
    }
  
    port.postMessage({
      command: 'instrument',
      type: 'memory'
    });
    window.close();
  }
docs: Toggles instrumented memory tracing.