Even though Google Chrome is installed, there is still something missing that is needed by Selenium. This is the "chromedriver". "chromedriver" can be downloaded on this website. Currently, the most recent version is 2.25. For instance, if one is using Windows, the file "chromedriver_win32.zip" needs to be downloaded.
When the file is downloaded, extract the file in it, i.e. "chromedriver.exe". Place "chromedriver.exe" where you want it to be. I put it in "User/Documents/R".
In the last step, you need to add the folder where "chromedriver.exe" is located to the system path. A description for adding a folder to the system path can be found here.
Now, one can restart R and run the code.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…