Remove some useless declarations

src/core/SkConvolver.cpp

 // Copyright (c) 2011 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.
 
 #include "SkConvolver.h"
 #include "SkTArray.h"
 
 namespace {
 
     // Converts the argument to an 8-bit unsigned value by clamping to the range
     // 0-255.
     inline unsigned char ClampTo8(int a) {
         if (static_cast<unsigned>(a) < 256) {
             return a;  // Avoid the extra check in the common case.
         }
-        if (a < 0) {
-            return 0;
-        }
         return 255;
     }
 
     // Stores a list of rows in a circular buffer. The usage is you write into it
     // by calling AdvanceRow. It will keep track of which row in the buffer it
     // should use next, and the total number of rows added.
     class CircularRowBuffer {
     public:
         // The number of pixels in each row is given in |sourceRowPixelWidth|.
         // The maximum number of rows needed in the buffer is |maxYFilterSize|
@@ skipping 448 matching lines @@
                                                sourceHasAlpha);
         } else {
             ConvolveVertically(filterValues, filterLength,
                                firstRowForFilter,
                                filterX.numValues(), curOutputRow,
                                sourceHasAlpha);
         }
     }
     return true;
 }