Add missing (and remove superfluous) 'explicit' from constructors.

base/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 time, 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
@@ skipping 223 matching lines @@
                        //   seconds which may take it up to 60).
     int millisecond;   // Milliseconds within the current second (0-999)
 
     // A cursory test for whether the data members are within their
     // respective ranges. A 'true' return value does not guarantee the
     // Exploded value can be successfully converted to a Time value.
     bool HasValidValues() const;
   };
 
   // Contains the NULL time. Use Time::Now() to get the current time.
-  explicit Time() : us_(0) {
+  Time() : us_(0) {
   }
 
   // Returns true if the time object has not been initialized.
   bool is_null() const {
     return us_ == 0;
   }
 
   // Returns true if the time object is the maximum time.
   bool is_max() const {
     return us_ == std::numeric_limits<int64>::max();
@@ skipping 379 matching lines @@
 #endif
 };
 
 inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
   return TimeTicks(t.ticks_ + delta_);
 }
 
 }  // namespace base
 
 #endif  // BASE_TIME_H_