Bug 1059343

Description of problem:
running a loop that changes the resolution enlarges the amount of memoty gnome-shell is using.

Version-Release number of selected component (if applicable):
gnome-shell-3.8.4-21.el7.x86_64

Tested on VM with qxl and with cirrus, and on a Lenovo T520 physical machine

How reproducible:
5/5

Steps to Reproduce:
1. On one gnome-terminal run top -p $(pgrep gnome-shell)
2. On a second gnome-terminal run resolution change in a loop (see script below)
3. See memory usage of gnome-shell getting bigger

script:
#!/bin/bash

V=$(xrandr | awk '$2 ~ /^connected/ {print $1}' | head -1)
MODES_TO_CHECK="1024x768 800x600 1440x900 640x480 1280x1024"
MODES=""
for m in $MODES_TO_CHECK; do
    if xrandr | grep -q $m; then
        MODES="$MODES $m"
    fi
done

function setmode () {
    xrandr --output $V --mode $1
    sleep 3
}

for i in $(req 1 100); do
    for m in $MODES; do
        echo $i $m
        setmode $m
    done
done

Actual results:
Memory used is getting larger

Expected results:
Memory used is not getting larger