UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36

Steps to reproduce the problem:
1. Put "foo" into the primary X clipboard and display when it is queried by running

$ echo "foo" | xclip -verbose

in a terminal.
2. Past via middle click into any text box in a website displayed in Google Chrome
3. The output of the above command is

Connected to X server.
Using UTF8_STRING.
Waiting for selection requests, Control-C to quit
  Waiting for selection request number 1
  Waiting for selection request number 2
  Waiting for selection request number 3

indicating that Chrome queries the X primary clipboard twice.

What is the expected behavior?
With previous versions of Chrome queried the X clipboard only once, resulting in the output 

Connected to X server.
Using UTF8_STRING.
Waiting for selection requests, Control-C to quit
  Waiting for selection request number 1
  Waiting for selection request number 2

What went wrong?
Apparently Chrome is querying the X primary selection twice.

This annoyingly breaks third party password manages such as pwsafe that copy the username to the X clipboard, wait until it was pasted, then copy the password to the clipboard, wait until it was pasted, and then exit. When such a password manager is used with the new version of chrome, after middle clicking into the "username" text field on a website, Chrome discards the username and instead puts the password in the username box. 

Did this work before? Yes I think the problem was introduced with the update google-chrome-stable:amd64 59.0.3071.115-1 -> 60.0.3112.90-1

Chrome version: 60.0.3112.90  Channel: stable
OS Version: Debian
Flash Version: