Add a history state update example to key_silk_cases

Add a history state update example to key_silk_cases

Updating the history state has been a surprisingly rich source of performance
bugs. This minimal page exemplifies them.

BUG=391158
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=282291

[wiltzius, 2014-07-08 08:59:20]

Per Nat's request adding the history state example to key_silk_cases

[Sami, 2014-07-08 11:18:37]

By the way, for really simple pages like this we've just made a local copy of
the html in tools/perf/page_sets/key_silk_cases (for example). It's ever so
slightly more convenient to work with than a .wpr.

https://codereview.chromium.org/378803002/diff/1/tools/perf/page_sets/key_sil...
File tools/perf/page_sets/key_silk_cases.py (right):

https://codereview.chromium.org/378803002/diff/1/tools/perf/page_sets/key_sil...
tools/perf/page_sets/key_silk_cases.py:573:
url='http://wiltzius.github.io/shape-shifter/',
This is from a different patch, right? It's not in the .wpr list at least.

[nduca, 2014-07-08 23:25:46]

i'm fine with this being in the wpr, skyostil for the final review, i think he's
right that yer git got confused :)

[wiltzius, 2014-07-09 04:39:18]

Sigh, one day I'll master branch history.

[Sami, 2014-07-09 13:07:06]

lgtm!

[wiltzius, 2014-07-10 02:38:02]

The CQ bit was checked by wiltzius@chromium.org

[commit-bot: I haz the power, 2014-07-10 02:39:06]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/wiltzius@chromium.org/378803002/20001

[commit-bot: I haz the power, 2014-07-10 08:24:44]

Change committed as 282291