[MD History] Fix toolbar dates in grouped mode.

base/i18n/time_formatting.h

Index: base/i18n/time_formatting.h
diff --git a/base/i18n/time_formatting.h b/base/i18n/time_formatting.h
index 761dd98a5d427e8441b7b17405be2dcb39933a6b..26daf2fa6ff669653a078d072734ebbf4c5dbb74 100644
--- a/base/i18n/time_formatting.h
+++ b/base/i18n/time_formatting.h
@@ -37,6 +37,15 @@ enum DurationFormatWidth {
   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);
 
@@ -62,6 +71,9 @@ 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
@@ -80,6 +92,10 @@ BASE_I18N_EXPORT string16 TimeFormatFriendlyDate(const Time& time);
 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).