Simplify SMILTime operators

Source/core/svg/animation/SMILTime.h

 /*
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 78 matching lines @@
 inline bool operator!=(const SMILTime& a, const SMILTime& b) { return !operator==(a, b); }
 
 // Ordering of SMILTimes has to follow: finite < indefinite (Inf) < unresolved (NaN). The first comparison is handled by IEEE754 but
 // NaN values must be checked explicitly to guarantee that unresolved is ordered correctly too.
 inline bool operator>(const SMILTime& a, const SMILTime& b) { return a.isUnresolved() || (a.value() > b.value()); }
 inline bool operator<(const SMILTime& a, const SMILTime& b) { return operator>(b, a); }
 inline bool operator>=(const SMILTime& a, const SMILTime& b) { return operator>(a, b) || operator==(a, b); }
 inline bool operator<=(const SMILTime& a, const SMILTime& b) { return operator<(a, b) || operator==(a, b); }
 inline bool operator<(const SMILTimeWithOrigin& a, const SMILTimeWithOrigin& b) { return a.time() < b.time(); }
 
-SMILTime operator+(const SMILTime&, const SMILTime&);
-SMILTime operator-(const SMILTime&, const SMILTime&);
+inline SMILTime operator+(const SMILTime& a, const SMILTime& b) { return a.value() + b.value(); }
+inline SMILTime operator-(const SMILTime& a, const SMILTime& b) { return a.value() - b.value(); }
 // So multiplying times does not make too much sense but SMIL defines it for duration * repeatCount
 SMILTime operator*(const SMILTime&, const SMILTime&);
 
 inline bool operator!=(const SMILInterval& a, const SMILInterval& b)
 {
     // Compare the "raw" values since the operator!= for SMILTime always return
     // true for non-finite times.
     return a.begin.value() != b.begin.value() || a.end.value() != b.end.value();
 }
 
@@ skipping 13 matching lines @@
 
 template<> struct HashTraits<blink::SMILTime> : GenericHashTraits<blink::SMILTime> {
     static blink::SMILTime emptyValue() { return blink::SMILTime::unresolved(); }
     static void constructDeletedValue(blink::SMILTime& slot) { slot = -std::numeric_limits<double>::infinity(); }
     static bool isDeletedValue(blink::SMILTime value) { return value == -std::numeric_limits<double>::infinity(); }
 };
 
 } // namespace WTF
 
 #endif // SMILTime_h