<div _ngcontent-c0="" class="header-actions">
    <!---->
    <clr-dropdown _ngcontent-c0="" class="dropdown" style="position: static;">
        <button _ngcontent-c0="" class="nav-text dropdown-toggle"
            clrdropdowntrigger="">
        <span _ngcontent-c0="">User Name</span>
        <!---->
        </button>
        <!---->
    </clr-dropdown>
</div>

1.1    element(by.css('nav-text dropdown-toggle')).click();
1.2    element(by.css('.nav-text dropdown-toggle')).click();
1.3    element(by.css("//span[. = 'User Name']")).click();
1.4    element(by.xpath("//span[. = 'User Name']")).click();



2. var logUser = $("div.header-actions  clr-dropdown.dropdown button span"),
       EC = protractor.ExpectedConditions;
       browser.wait(EC.visibilityOf(logUser), 5000);
       logUser.click();