remove unused SkBitmapFilter::Allocate

src/core/SkBitmapFilter.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkBitmapFilter_DEFINED
 #define SkBitmapFilter_DEFINED
 
@@ skipping 47 matching lines @@
         for (int index = 0; index < count; index++) {
             float filterValue = evaluate(val);
             *output++ = filterValue;
             sum += filterValue;
             val += diff;
         }
         return sum;
     }
 #endif
 
-    static SkBitmapFilter* Allocate();
-
 protected:
     float fWidth;
     float fInvWidth;
     float fLookupMultiplier;
 
     mutable bool fPrecomputed;
     mutable SkFixed fFilterTable[SKBITMAP_FILTER_TABLE_SIZE];
     mutable SkScalar fFilterTableScalar[SKBITMAP_FILTER_TABLE_SIZE];
 
 private:
@@ skipping 165 matching lines @@
             return 1.0f;  // Special case the discontinuity at the origin.
         }
         float xpi = x * static_cast<float>(SK_ScalarPI);
         return (sk_float_sin(xpi) / xpi) *  // sinc(x)
                sk_float_sin(xpi / fWidth) / (xpi / fWidth);  // sinc(x/fWidth)
     }
 };
 
 
 #endif