Add logging support for base::Time* types.

base/time/time.h

 // Copyright (c) 2012 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.
 
 // Time represents an absolute point in coordinated universal time (UTC),
 // internally represented as microseconds (s/1,000,000) since the Windows epoch
 // (1601-01-01 00:00:00 UTC) (See http://crbug.com/14734).  System-dependent
 // clock interface routines are defined in time_PLATFORM.cc.
 //
 // TimeDelta represents a duration of time, internally represented in
 // microseconds.
 //
 // TimeTicks represents an abstract time that is most of the time incrementing
 // for use in measuring time durations. It is internally represented in
 // microseconds.  It can not be converted to a human-readable time, but is
 // guaranteed not to decrease (if the user changes the computer clock,
 // Time::Now() may actually decrease or jump).  But note that TimeTicks may
 // "stand still", for example if the computer suspended.
 //
 // These classes are represented as only a 64-bit value, so they can be
 // efficiently passed by value.
+//
+// Definitions of operator<< are provided to make these types work with
+// DCHECK_EQ() and other log macros. For human-readable formatting, see
+// "base/i18n/time_formatting.h".
 
 #ifndef BASE_TIME_TIME_H_
 #define BASE_TIME_TIME_H_
 
 #include <time.h>
 
+#include <iosfwd>
+
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "build/build_config.h"
 
 #if defined(OS_MACOSX)
 #include <CoreFoundation/CoreFoundation.h>
 // Avoid Mac system header macro leak.
 #undef TYPE_BOOL
 #endif
 
@@ skipping 161 matching lines @@
   }
 
   // Delta in microseconds.
   int64 delta_;
 };
 
 inline TimeDelta operator*(int64 a, TimeDelta td) {
   return TimeDelta(a * td.delta_);
 }
 
+// For logging use only.
+BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeDelta time_delta);
+
 // Time -----------------------------------------------------------------------
 
 // Represents a wall clock time in UTC.
 class BASE_EXPORT Time {
  public:
   static const int64 kMillisecondsPerSecond = 1000;
   static const int64 kMicrosecondsPerMillisecond = 1000;
   static const int64 kMicrosecondsPerSecond = kMicrosecondsPerMillisecond *
                                               kMillisecondsPerSecond;
   static const int64 kMicrosecondsPerMinute = kMicrosecondsPerSecond * 60;
@@ skipping 335 matching lines @@
   // Preserve max to prevent overflow.
   if (us == std::numeric_limits<int64>::max())
     return Max();
   return TimeDelta(us);
 }
 
 inline Time TimeDelta::operator+(Time t) const {
   return Time(t.us_ + delta_);
 }
 
+// For logging use only.
+BASE_EXPORT std::ostream& operator<<(std::ostream& os, Time time);
+
 // TimeTicks ------------------------------------------------------------------
 
 class BASE_EXPORT TimeTicks {
  public:
   // We define this even without OS_CHROMEOS for seccomp sandbox testing.
 #if defined(OS_LINUX)
   // Force definition of the system trace clock; it is a chromeos-only api
   // at the moment and surfacing it in the right place requires mucking
   // with glibc et al.
   static const clockid_t kClockSystemTrace = 11;
@@ skipping 142 matching lines @@
 #if defined(OS_WIN)
   typedef DWORD (*TickFunctionType)(void);
   static TickFunctionType SetMockTickFunction(TickFunctionType ticker);
 #endif
 };
 
 inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
   return TimeTicks(t.ticks_ + delta_);
 }
 
+// For logging use only.
+BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks);
+
 }  // namespace base
 
 #endif  // BASE_TIME_TIME_H_