[MD History] Fix toolbar dates in grouped mode.

base/i18n/time_formatting.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Basic time formatting methods.  These methods use the current locale
 // formatting for displaying the time.
 
 #ifndef BASE_I18N_TIME_FORMATTING_H_
 #define BASE_I18N_TIME_FORMATTING_H_
 
@@ skipping 19 matching lines @@
 
 // Should match UMeasureFormatWidth in measfmt.h; replicated here to avoid
 // requiring third_party/icu dependencies with this file.
 enum DurationFormatWidth {
   DURATION_WIDTH_WIDE,    // "3 hours, 7 minutes"
   DURATION_WIDTH_SHORT,   // "3 hr, 7 min"
   DURATION_WIDTH_NARROW,  // "3h 7m"
   DURATION_WIDTH_NUMERIC  // "3:07"
 };
 
+// Date formats from third_party/icu/source/i18n/unicode/udat.h. Add more as
+// necessary.
+enum DateFormat {
+  // November 2007
+  DATE_FORMAT_YEAR_MONTH,
+  // Tuesday, 7 November
+  DATE_FORMAT_MONTH_WEEKDAY_DAY,
+};
+
 // Returns the time of day, e.g., "3:07 PM".
 BASE_I18N_EXPORT string16 TimeFormatTimeOfDay(const Time& time);
 
 // Returns the time of day in 24-hour clock format with millisecond accuracy,
 // e.g., "15:07:30.568"
 BASE_I18N_EXPORT string16 TimeFormatTimeOfDayWithMilliseconds(const Time& time);
 
 // Returns the time of day in the specified hour clock type. e.g.
 // "3:07 PM" (type == k12HourClock, ampm == kKeepAmPm).
 // "3:07"    (type == k12HourClock, ampm == kDropAmPm).
 // "15:07"   (type == k24HourClock).
 BASE_I18N_EXPORT string16 TimeFormatTimeOfDayWithHourClockType(
     const Time& time,
     HourClockType type,
     AmPmClockType ampm);
 
 // Returns a shortened date, e.g. "Nov 7, 2007"
 BASE_I18N_EXPORT string16 TimeFormatShortDate(const Time& time);
 
 // Returns a numeric date such as 12/13/52.
 BASE_I18N_EXPORT string16 TimeFormatShortDateNumeric(const Time& time);
 
 // Returns a numeric date and time such as "12/13/52 2:44:30 PM".
 BASE_I18N_EXPORT string16 TimeFormatShortDateAndTime(const Time& time);
 
+// Returns a month and year, e.g. "November 2007"
+BASE_I18N_EXPORT string16 TimeFormatMonthAndYear(const Time& time);
+
 // Returns a numeric date and time with time zone such as
 // "12/13/52 2:44:30 PM PST".
 BASE_I18N_EXPORT string16
 TimeFormatShortDateAndTimeWithTimeZone(const Time& time);
 
 // Formats a time in a friendly sentence format, e.g.
 // "Monday, March 6, 2008 2:44:30 PM".
 BASE_I18N_EXPORT string16 TimeFormatFriendlyDateAndTime(const Time& time);
 
 // Formats a time in a friendly sentence format, e.g.
@@ skipping 17 matching lines @@
 //
 // Please don't use width = DURATION_WIDTH_NUMERIC when the time duration
 // can possibly be larger than 24h, as the hour value will be cut below 24
 // after formatting.
 // TODO(chengx): fix function output when width = DURATION_WIDTH_NUMERIC
 // (http://crbug.com/675791)
 BASE_I18N_EXPORT string16
 TimeDurationFormatWithSeconds(const TimeDelta time,
                               const DurationFormatWidth width);
 
+// Formats a date interval into various formats, e.g. "2 December - 4 December"
+// or "March 2016 - December 2016". See DateFormat for details.
+BASE_I18N_EXPORT string16 DateIntervalFormat(const Time& begin_time,
+                                             const Time& end_time,
+                                             DateFormat format);
+
 // Gets the hour clock type of the current locale. e.g.
 // k12HourClock (en-US).
 // k24HourClock (en-GB).
 BASE_I18N_EXPORT HourClockType GetHourClockType();
 
 }  // namespace base
 
 #endif  // BASE_I18N_TIME_FORMATTING_H_