[MD History] Fix toolbar dates in grouped mode.

base/i18n/time_formatting.cc

Index: base/i18n/time_formatting.cc
diff --git a/base/i18n/time_formatting.cc b/base/i18n/time_formatting.cc
index 024b86510b5a8260565dbd02eaaa376949de22a3..5be877a5170f3af5a690b02f88692b54c0e45888 100644
--- a/base/i18n/time_formatting.cc
+++ b/base/i18n/time_formatting.cc
@@ -12,6 +12,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "third_party/icu/source/i18n/unicode/datefmt.h"
+#include "third_party/icu/source/i18n/unicode/dtitvfmt.h"
 #include "third_party/icu/source/i18n/unicode/dtptngen.h"
 #include "third_party/icu/source/i18n/unicode/fmtable.h"
 #include "third_party/icu/source/i18n/unicode/measfmt.h"
@@ -81,6 +82,17 @@ UMeasureFormatWidth DurationWidthToMeasureWidth(DurationFormatWidth width) {
   return UMEASFMT_WIDTH_COUNT;
 }
 
+const char* DateFormatToString(DateFormat format) {
+  switch (format) {
+    case DATE_FORMAT_YEAR_MONTH:
+      return UDAT_YEAR_MONTH;
+    case DATE_FORMAT_MONTH_WEEKDAY_DAY:
+      return UDAT_MONTH_WEEKDAY_DAY;
+  }
+  NOTREACHED();
+  return UDAT_YEAR_MONTH_DAY;
+}
+
 }  // namespace
 
 string16 TimeFormatTimeOfDay(const Time& time) {
@@ -141,6 +153,12 @@ string16 TimeFormatShortDateAndTimeWithTimeZone(const Time& time) {
   return TimeFormat(formatter.get(), time);
 }
 
+string16 TimeFormatMonthAndYear(const Time& time) {
+  icu::SimpleDateFormat formatter =
+      CreateSimpleDateFormatter(DateFormatToString(DATE_FORMAT_YEAR_MONTH));
+  return TimeFormat(&formatter, time);
+}
+
 string16 TimeFormatFriendlyDateAndTime(const Time& time) {
   std::unique_ptr<icu::DateFormat> formatter(
       icu::DateFormat::createDateTimeInstance(icu::DateFormat::kFull));
@@ -171,6 +189,25 @@ string16 TimeDurationFormat(const TimeDelta& time,
   return base::string16(formatted.getBuffer(), formatted.length());
 }
 
+string16 DateIntervalFormat(const Time& begin_time,
+                            const Time& end_time,
+                            DateFormat format) {
+  UErrorCode status = U_ZERO_ERROR;
+
+  std::unique_ptr<icu::DateIntervalFormat> formatter(
+      icu::DateIntervalFormat::createInstance(DateFormatToString(format),
+                                              status));
+
+  icu::FieldPosition pos = 0;
+  UDate start_date = static_cast<UDate>(begin_time.ToDoubleT() * 1000);
+  UDate end_date = static_cast<UDate>(end_time.ToDoubleT() * 1000);
+  icu::DateInterval interval(start_date, end_date);
+  icu::UnicodeString formatted;
+  formatter->format(&interval, formatted, pos, status);
+  return string16(formatted.getBuffer(),
+                  static_cast<size_t>(formatted.length()));
+}
+
 HourClockType GetHourClockType() {
   // TODO(satorux,jshin): Rework this with ures_getByKeyWithFallback()
   // once it becomes public. The short time format can be found at