[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,
+};

[jungshik at Google, 2017/01/10 01:12:29]

I have a mixed feeling about insulating callers from ICU enums. If there's a
non-ICU implementation, it makes a perfect sense, but we don't have any.   I'm
aware that other APIs do something similar here. 

[calamity, 2017/01/16 02:49:25]

I would prefer the ICU enums get hidden, just because they're harder to find.
Figuring out that you need to include e.g dtitvfmt.h, isn't something I'd want
all clients of this code to have to think about. I think they should have a
chrome API that's nicely insulated from the grittier ICU implementation details.

+
 // 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.
 // "Monday, March 6, 2008".
 BASE_I18N_EXPORT string16 TimeFormatFriendlyDate(const Time& time);
 
 // Formats a time duration of hours and minutes into various formats, e.g.,
 // "3:07" or "3 hours, 7 minutes".  See DurationFormatWidth for details.
 BASE_I18N_EXPORT string16 TimeDurationFormat(const TimeDelta& time,
                                              const DurationFormatWidth width);
 
+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_