Added a timezone policy and pyauto tests for it.

chrome/browser/automation/testing_automation_provider.h

Index: chrome/browser/automation/testing_automation_provider.h
diff --git a/chrome/browser/automation/testing_automation_provider.h b/chrome/browser/automation/testing_automation_provider.h
index 11f428f6ab236fd859ffe575edc974386eb82ccb..4dd6dfa86686437e16d1d08e7b2519c903a06052 100644
--- a/chrome/browser/automation/testing_automation_provider.h
+++ b/chrome/browser/automation/testing_automation_provider.h
@@ -1601,6 +1601,14 @@ class TestingAutomationProvider : public AutomationProvider,
   // Html terminal.
   void OpenCrosh(base::DictionaryValue* args, IPC::Message* reply_message);
 
+  // Set ChromeOS Settings.
+  // Uses the JSON interface for input/output.
+  // Sample json input:
+  // { "command": "SetCrosSetting",
+  //   "path": path,
+  //   "value": value }
+  void SetCrosSetting(base::DictionaryValue* args, IPC::Message* reply_message);

[Joao da Silva, 2012/07/27 13:40:57]

This is a big hammer. We previously had a similar call to SetPolicies() and
ultimately decided to remove it.

Notice that there's already a SetTimezone() automation call, isn't it enough to
cover your test?

[pneubeck (no reviews), 2012/07/31 22:21:05]

The idea of this definition was to change chromeos settings (controlled by
CrosSettings) in the same fashion as normal settings are set using the function
SetPrefs. I see, that this means that policies can also be changed via the owner
of the device because these are also controlled by CrosSettings.
I don't see in which way this is problematic. Surely it is not really necessary
as long as the timezone test is the only use case. But the difference of the
generic function i provided and the a special function for timezone isn't that
huge... so why should I provide the special one?

The major difference between setting the timezone with this function and the
existing SetTimezone is, that this one talks to CrosSettings and the other to
the underlying chromeos::system::TimezoneSettings.

Depending on what we like to have, more a functional, integration or unit test,
both may be more appropriate. For functional tests, which I wanted to implement
and many pyauto test seem to be, the new function should be proper.

Do you have any other suggestions or which of the variants do you think fits
better?

[pneubeck (no reviews), 2012/08/06 14:50:48]

Done.

+
   void AddChromeosObservers();
   void RemoveChromeosObservers();