Clarified description of the timezone policy.

chrome/browser/policy/proto/chrome_device_policy.proto

Index: chrome/browser/policy/proto/chrome_device_policy.proto
diff --git a/chrome/browser/policy/proto/chrome_device_policy.proto b/chrome/browser/policy/proto/chrome_device_policy.proto
index 262e85eec4db62e1e7715f0339f04c5dfd5f3dac..78aecd27a0e3800814da812a3ce71266a5452b3b 100644
--- a/chrome/browser/policy/proto/chrome_device_policy.proto
+++ b/chrome/browser/policy/proto/chrome_device_policy.proto
@@ -207,10 +207,16 @@ message StartUpUrlsProto {
 }
 
 message SystemTimezoneProto {
-  // Specifies the timezone which is applied if this value is provided. Valid
+  // The timezone device setting is active if this value is provided. Valid

[Mattias Nissler (ping if slow), 2012/08/21 09:19:06]

One last suggestion: "Specifies an owner-determined timezone that applies to the
login screen and all users."

   // values are listed in "timezone_settings.cc". Additionally, timezones from
   // the "IANA Time Zone Database" (e.g. listed on wikipedia) that are
-  // equivalent to one of the timezones in "timezone_settings.cc" are valid.
+  // equivalent to one of the timezones in "timezone_settings.cc" are valid. In
+  // case of an invalid value, the setting is still activated with a fallback
+  // timezone (currently "GMT").
+  // Only if no value is provided, the timezone device setting is inactive. In
+  // that case, the currently active timezone will remain in use however users
+  // can change the timezone and the change is persistent. Thus a change by one
+  // user affects the login-screen and all other users.
   optional string timezone = 1;
 }