Add support for 12/24 hour clock switching on Chrome OS.

Introduce "[ ] Use 24-hour clock" setting in the Chrome OS system settings.

The English (United States) locale (en-US) uses 12 hour clock like "15:07 PM"
by default, and there was no way to customize the format.  With this change,
users will be able to change it to 24 hour clock.

Likewise, The English (United Kingdom) locale (en-GB) uses 24 hour clock by
default. Users will also be able to change it to 12 hour clock.

BUG=chromium-os:10534
TEST=confirmed that the 12/24 hour clock switching worked.

Review URL: http://codereview.chromium.org/6834019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@81593 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 73 insertions, 1 deletions

diff --git a/chrome/browser/chromeos/preferences.cc b/chrome/browser/chromeos/preferences.cc
index 46285ae..6ae904f 100644
--- a/chrome/browser/chromeos/preferences.cc
+++ b/chrome/browser/chromeos/preferences.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/chromeos/preferences.h"
 
+#include "base/i18n/time_formatting.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
@@ -42,6 +43,9 @@ void Preferences::RegisterUserPrefs(PrefService* prefs) {
     prefs->RegisterBooleanPref(prefs::kAccessibilityEnabled, false);
   }
   prefs->RegisterIntegerPref(prefs::kTouchpadSensitivity, 3);
+  // Set the default based on the hour clock type of the current locale.
+  prefs->RegisterBooleanPref(prefs::kUse24HourClock,
+                             base::GetHourClockType() == base::k24HourClock);
   prefs->RegisterStringPref(prefs::kLanguageCurrentInputMethod, "");
   prefs->RegisterStringPref(prefs::kLanguagePreviousInputMethod, "");
   prefs->RegisterStringPref(prefs::kLanguageHotkeyNextEngineInMenu,
@@ -129,6 +133,7 @@ void Preferences::Init(PrefService* prefs) {
   tap_to_click_enabled_.Init(prefs::kTapToClickEnabled, prefs, this);
   accessibility_enabled_.Init(prefs::kAccessibilityEnabled, prefs, this);
   sensitivity_.Init(prefs::kTouchpadSensitivity, prefs, this);
+  use_24hour_clock_.Init(prefs::kUse24HourClock, prefs, this);
   language_hotkey_next_engine_in_menu_.Init(
       prefs::kLanguageHotkeyNextEngineInMenu, prefs, this);
   language_hotkey_previous_engine_.Init(
diff --git a/chrome/browser/chromeos/preferences.h b/chrome/browser/chromeos/preferences.h
index f6c6b55..bf97ac9 100644
--- a/chrome/browser/chromeos/preferences.h
+++ b/chrome/browser/chromeos/preferences.h
@@ -87,6 +87,7 @@ class Preferences : public NotificationObserver {
   BooleanPrefMember accessibility_enabled_;
   IntegerPrefMember speed_factor_;
   IntegerPrefMember sensitivity_;
+  BooleanPrefMember use_24hour_clock_;
 
   // Input method preferences.
   StringPrefMember language_hotkey_next_engine_in_menu_;
diff --git a/chrome/browser/chromeos/status/clock_menu_button.cc b/chrome/browser/chromeos/status/clock_menu_button.cc
index 45a2662..54ae8d7 100644
--- a/chrome/browser/chromeos/status/clock_menu_button.cc
+++ b/chrome/browser/chromeos/status/clock_menu_button.cc
@@ -10,6 +10,11 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/chromeos/cros/cros_library.h"
 #include "chrome/browser/chromeos/status/status_area_host.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
+#include "content/common/notification_details.h"
+#include "content/common/notification_source.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -34,6 +39,11 @@ ClockMenuButton::ClockMenuButton(StatusAreaHost* host)
   // Add as SystemLibrary observer. We update the clock if timezone changes.
   CrosLibrary::Get()->GetSystemLibrary()->AddObserver(this);
   CrosLibrary::Get()->GetPowerLibrary()->AddObserver(this);
+  // Start monitoring the kUse24HourClock preference.
+  if (host->GetProfile()) {  // This can be NULL in the login screen.
+    registrar_.Init(host->GetProfile()->GetPrefs());
+    registrar_.Add(prefs::kUse24HourClock, this);
+  }
 
   set_border(NULL);
   set_use_menu_button_paint(true);
@@ -76,12 +86,37 @@ void ClockMenuButton::UpdateTextAndSetNextTimer() {
 
 void ClockMenuButton::UpdateText() {
   base::Time time(base::Time::Now());
-  SetText(UTF16ToWide(base::TimeFormatTimeOfDay(time)));
+  // If the profie is present, check the use 24-hour clock preference.
+  if (host_->GetProfile()) {  // This can be NULL in the login screen.
+    const bool use_24hour_clock =
+        host_->GetProfile()->GetPrefs()->GetBoolean(prefs::kUse24HourClock);
+    base::HourClockType clock_type = (use_24hour_clock ?
+                                      base::k24HourClock : base::k12HourClock);
+    SetText(UTF16ToWide(base::TimeFormatTimeOfDayWithHourClockType(
+        time, clock_type)));
+  } else {
+    SetText(UTF16ToWide(base::TimeFormatTimeOfDay(time)));
+  }
   SetTooltipText(UTF16ToWide(base::TimeFormatShortDate(time)));
   SchedulePaint();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// ClockMenuButton, NotificationObserver implementation:
+
+void ClockMenuButton::Observe(NotificationType type,
+                              const NotificationSource& source,
+                              const NotificationDetails& details) {
+  if (type == NotificationType::PREF_CHANGED) {
+    std::string* pref_name = Details<std::string>(details).ptr();
+    if (*pref_name == prefs::kUse24HourClock) {
+      UpdateText();
+    }
+  }
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
 // ClockMenuButton, ui::MenuModel implementation:
 
 int ClockMenuButton::GetItemCount() const {
diff --git a/chrome/browser/chromeos/status/clock_menu_button.h b/chrome/browser/chromeos/status/clock_menu_button.h
index f8d5a1f..778dcf8 100644
--- a/chrome/browser/chromeos/status/clock_menu_button.h
+++ b/chrome/browser/chromeos/status/clock_menu_button.h
@@ -11,6 +11,10 @@
 #include "chrome/browser/chromeos/cros/power_library.h"
 #include "chrome/browser/chromeos/cros/system_library.h"
 #include "chrome/browser/chromeos/status/status_area_button.h"
+#include "chrome/browser/prefs/pref_change_registrar.h"
+#include "chrome/browser/prefs/pref_member.h"
+#include "content/common/notification_observer.h"
+#include "content/common/notification_type.h"
 #include "unicode/calendar.h"
 #include "views/controls/button/menu_button.h"
 #include "views/controls/menu/menu_2.h"
@@ -25,6 +29,7 @@ class StatusAreaHost;
 class ClockMenuButton : public StatusAreaButton,
                         public views::ViewMenuDelegate,
                         public ui::MenuModel,
+                        public NotificationObserver,
                         public PowerLibrary::Observer,
                         public SystemLibrary::Observer {
  public:
@@ -67,6 +72,11 @@ class ClockMenuButton : public StatusAreaButton,
   // changes.
   void UpdateText();
 
+  // NotificationObserver implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
  protected:
   virtual int horizontal_padding() { return 3; }
 
@@ -86,6 +96,8 @@ class ClockMenuButton : public StatusAreaButton,
 
   StatusAreaHost* host_;
 
+  PrefChangeRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(ClockMenuButton);
 };
 
diff --git a/chrome/browser/resources/options/chromeos/system_options.html b/chrome/browser/resources/options/chromeos/system_options.html
index a775a2e..9ab473b 100644
--- a/chrome/browser/resources/options/chromeos/system_options.html
+++ b/chrome/browser/resources/options/chromeos/system_options.html
@@ -11,6 +11,18 @@
              dataType="string"
              pref="cros.system.timezone"></select>
         </td>
+      <tr>
+        <td class="option-name" colspan="2">
+          <div class="checkbox">
+            <label>
+              <input id="use-24hour-clock"
+                  pref="settings.clock.use_24hour_clock"
+                  type="checkbox">
+              <span i18n-content="use_24hour_clock"></span>
+            </label>
+          </div>
+        </td>
+      </tr>
       </tr>
     </table>
   </section>
diff --git a/chrome/browser/sync/glue/synchronized_preferences.h b/chrome/browser/sync/glue/synchronized_preferences.h
index b9429c3..beb8166 100644
--- a/chrome/browser/sync/glue/synchronized_preferences.h
+++ b/chrome/browser/sync/glue/synchronized_preferences.h
@@ -193,6 +193,10 @@ static const char* kSynchronizedPreferences[] = {
   // Whether to enable tap-to-click
   //   Settings -> System -> Touchpad
   prefs::kTapToClickEnabled,
+
+  // Whether to use the 24-hour clock format.
+  //   Settings -> System -> Date and Time
+  prefs::kUse24HourClock,
 #endif
 };
 
diff --git a/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc b/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
index 921e138..00d6133 100644
--- a/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
+++ b/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
@@ -39,6 +39,9 @@ void SystemOptionsHandler::GetLocalizedValues(
       l10n_util::GetStringUTF16(IDS_OPTIONS_SETTINGS_SECTION_TITLE_DATETIME));
   localized_strings->SetString("timezone",
       l10n_util::GetStringUTF16(IDS_OPTIONS_SETTINGS_TIMEZONE_DESCRIPTION));
+  localized_strings->SetString("use_24hour_clock",
+      l10n_util::GetStringUTF16(
+          IDS_OPTIONS_SETTINGS_USE_24HOUR_CLOCK_DESCRIPTION));
 
   localized_strings->SetString("touchpad",
       l10n_util::GetStringUTF16(IDS_OPTIONS_SETTINGS_SECTION_TITLE_TOUCHPAD));