Add SkTPin.

include/core/SkTypes.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTypes_DEFINED
 #define SkTypes_DEFINED
 
@@ skipping 382 matching lines @@
     return (a >> 31) | ((unsigned) -a >> 31);
 }
 
 static inline int32_t SkFastMin32(int32_t value, int32_t max) {
     if (value > max) {
         value = max;
     }
     return value;
 }
 
-/** Returns signed 32 bit value pinned between min and max, inclusively
-*/
+template <typename T> static inline const T& SkTPin(const T& x, const T& min, const T& max) {
+    return SkTMax(SkTMin(x, max), min);
+}
+
+/** Returns signed 32 bit value pinned between min and max, inclusively. */
 static inline int32_t SkPin32(int32_t value, int32_t min, int32_t max) {
-    if (value < min) {
-        value = min;
-    }
-    if (value > max) {
-        value = max;
-    }
-    return value;
+    return SkTPin(value, min, max);
 }
 
 static inline uint32_t SkSetClearShift(uint32_t bits, bool cond,
                                        unsigned shift) {
     SkASSERT((int)cond == 0 || (int)cond == 1);
     return (bits & ~(1 << shift)) | ((int)cond << shift);
 }
 
 static inline uint32_t SkSetClearMask(uint32_t bits, bool cond,
                                       uint32_t mask) {
@@ skipping 249 matching lines @@
 private:
     void*       fPtr;
     size_t      fSize;  // can be larger than the requested size (see kReuse)
     uint32_t    fStorage[(kSize + 3) >> 2];
 };
 // Can't guard the constructor because it's a template class.
 
 #endif /* C++ */
 
 #endif