Add --properties for things like gitHash that describe the current nanobench run.

--key describes the type of run (describes the line on the chart), --properties
describes the run itself (describes the dot on the chart).

We'll pass --properties gitHash <git hash> build_number <build number>  --key
... to nanobench from the bots.

And... delete a whole lot of dead code.

Example: nanobench --properties gitHash foo build_number 1234 --key bar baz

{
   "build_number" : "1234",
   "gitHash" : "foo",
   "key" : {
      "bar" : "baz"
   },
   "results" : {
....

Friends with https://codereview.chromium.org/491943002
BUG=skia:
R=jcgregorio@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/488213002
7 files changed