Add logging support for base::Time* types.

base/time/time.h

Index: base/time/time.h
diff --git a/base/time/time.h b/base/time/time.h
index 3cf3746166ed8dc16cc937945d0918cfe6ef8ede..641f465af3e471afc3b4833b2c6b2a9faf122d8e 100644
--- a/base/time/time.h
+++ b/base/time/time.h
@@ -19,12 +19,18 @@
 //
 // 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"
@@ -206,6 +212,9 @@ 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.
@@ -561,6 +570,9 @@ 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 {
@@ -723,6 +735,9 @@ 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_