Implemented a "Last Updated" field for the about page of Chrome OS.

chrome/browser/ui/webui/help/help_handler.cc

Index: chrome/browser/ui/webui/help/help_handler.cc
diff --git a/chrome/browser/ui/webui/help/help_handler.cc b/chrome/browser/ui/webui/help/help_handler.cc
index 6f3a246be2f659665f21efb848e254bb3cae6b65..b2a985ef1ff19316dc7bd8def68d9380cab75950 100644
--- a/chrome/browser/ui/webui/help/help_handler.cc
+++ b/chrome/browser/ui/webui/help/help_handler.cc
@@ -21,6 +21,7 @@
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/url_constants.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/common/content_client.h"
@@ -34,6 +35,8 @@
 #include "webkit/glue/webkit_glue.h"
 
 #if defined(OS_CHROMEOS)
+#include "base/i18n/time_formatting.h"
+#include "base/sys_info.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/cros_settings.h"
 #include "chrome/browser/profiles/profile.h"
@@ -41,6 +44,7 @@
 #endif
 
 using base::ListValue;
+using content::BrowserThread;
 
 namespace {
 
@@ -90,6 +94,28 @@ bool CanChangeReleaseChannel() {
   return false;
 }
 
+// Retrieves the time of the last Chrome OS update and converts it to a human-
+// readable string. Note that this method uses an i18n-friendly library, so
+// the returned string will already be properly translated.
+string16 CreateLastUpdatedString() {
+  base::Time time;
+
+  if (!base::SysInfo::GetTimeLastUpdated(&time)) {
+    // If the time of the last update cannot be retrieved, punt and just set
+    // the last update time to be the current time.
+    time = base::Time::Now();
+  }
+
+  return base::TimeFormatFriendlyDate(time);
+}
+
+// Wrapper function to add the "Last Updated" string to |localized_strings|.
+// This function is called from the File thread to ensure that it does not
+// slow down the UI thread.
+void AddLastUpdatedString(DictionaryValue* localized_strings) {
+  localized_strings->SetString("lastUpdatedDate", CreateLastUpdatedString());
+}
+
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace
@@ -136,6 +162,7 @@ void HelpHandler::GetLocalizedValues(DictionaryValue* localized_strings) {
     { "webkit", IDS_WEBKIT },
     { "userAgent", IDS_ABOUT_VERSION_USER_AGENT },
     { "commandLine", IDS_ABOUT_VERSION_COMMAND_LINE },
+    { "lastUpdated", IDS_ABOUT_VERSION_LAST_UPDATED },
 #endif
 #if defined(OS_MACOSX)
     { "promote", IDS_ABOUT_CHROME_PROMOTE_UPDATER },
@@ -164,6 +191,9 @@ void HelpHandler::GetLocalizedValues(DictionaryValue* localized_strings) {
       IDS_ABOUT_CROS_VERSION_LICENSE,
       ASCIIToUTF16(chrome::kChromeUIOSCreditsURL));
   localized_strings->SetString("productOsLicense", os_license);
+
+  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
+      base::Bind(&AddLastUpdatedString, localized_strings));

[Evan Stade, 2012/04/16 19:42:51]

there is a race here, and besides which localized_strings is not thread safe

instead of adding the last updated time to localized_strings, you should create
a javascript function call to pass along that string. Also you should cache it,
so you only have to read from disk once

and I think you'll find FileUtilProxy to be pretty helpful

[Kyle Horimoto, 2012/04/17 18:31:45]

Done.

 #endif
 
   string16 tos = l10n_util::GetStringFUTF16(