Protractor: sendKeys with multiple keys (CTRL+a) no more working

Hi there!

Bug report

• Node Version: 7.5.0
• Protractor Version: 4.0.14
• Browser(s): Chrome 56 on centos 7 (idem for Firefox)
• Operating System and Version CentOS 7
• Your protractor configuration file:

'use strict';

var testiCommons = require('../utilit/testiCommons.js');

exports.config = {
    framework: 'mocha',
    seleniumAddress: 'http://localhost:4444/wd/hub',
    specs: ['../../../*/tests/protractor/**/*.js'],
    baseUrl: 'http://localhost:3001',
    getPageTimeout: 30000,
    allScriptsTimeout: 30000,
    mochaOpts: {
        timeout: 30000, // ms,
        reporter: 'spec',
        slow: '2000', // a test is slow if it takes over 1 sec to accomplish
        delay: true
    },

    capabilities: {
        // If this is set to be true, specs will be sharded by file (i.e. all
        // files to be run by this set of capabilities will run in parallel).
        // Default is false.
        shardTestFiles: false,

        // Maximum number of browser instances that can run in parallel for this
        // set of capabilities. This is only needed if shardTestFiles is true.
        // Default is 1.
        maxInstances: 1,

        browserName: 'chrome',
//        browserName: 'firefox',

        'chromeOptions': {
            // Get rid of --ignore-certificate yellow warning
            args: ['--no-sandbox', '--test-type=browser'],
            // --start-maximized

            // Set download path and avoid prompting for download even though
            // this is already the default on Chrome but for completeness
            prefs: {
                'download': {
                    'prompt_for_download': false,
                    'default_directory': '/datas/temp',
                }
            }
        }
    },

    onPrepare: function() {
    },

    onComplete: function() {
        console.log('Into global onComplete test function');
        testiCommons.disconnectMongo();
    },
};

• A relevant example test
  I try many combinaisons:
  $elt.sendKeys(webdriver.Key.CONTROL, 'a', webdriver.Key.NULL, keys);
  or

$elt.sendKeys(protractor.Key.chord(protractor.Key.CONTROL, 'a'));
$elt.sendKeys(keys);

or

browser.actions().keyDown(protractor.Key.CONTROL).sendKeys('a').perform();    
$elt.sendKeys(keys);
browser.actions().keyUp(protractor.Key.CONTROL).perform();

Both configurations don't work now (it was before) because CTRL+A (select text in field) is not selected.