The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/1b6ec435fef271dcd97b0b50fcc7e7788ef61a15

commit 1b6ec435fef271dcd97b0b50fcc7e7788ef61a15
Author: Aviv Keshet <akeshet@chromium.org>
Date: Wed Jul 18 11:08:11 2018

autotest: tko: delete obsolete graphing code

BUG= chromium:864821 
TEST=No results returned when grepping for remaining references to:
plotgraph, machine_[aggr,benchmark,test_attribute_graph], draw_graphs

Change-Id: I24af6e738fa61e68ce3a8eab903d85af641220d9
Reviewed-on: https://chromium-review.googlesource.com/1141222
Commit-Ready: Aviv Keshet <akeshet@chromium.org>
Tested-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>

[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/machine_benchmark.cgi
[modify] https://crrev.com/1b6ec435fef271dcd97b0b50fcc7e7788ef61a15/tko/display.py
[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/nightly.py
[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/machine_aggr.cgi
[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/draw_graphs
[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/plotgraph.py
[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/plotgraph
[delete] https://crrev.com/0a931caac805f598ade1fdf54a8f7aa189f82877/tko/machine_test_attribute_graph.cgi