fix warnings around size_t/int

src/core/SkDistanceFieldGen.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDistanceFieldGen.h"
 #include "SkPoint.h"
 
@@ skipping 311 matching lines @@
     } else if (dist > distanceMagnitude) {
         return 0;
     } else {
         return (unsigned char)((distanceMagnitude-dist)*128.0f/distanceMagnitude);
     }
 }
 #endif
 
 // assumes a padded 8-bit image and distance field
 // width and height are the original width and height of the image
-bool generate_distance_field_from_image(unsigned char* distanceField,
-                                        const unsigned char* copyPtr,
-                                        int width, int height) {
+static bool generate_distance_field_from_image(unsigned char* distanceField,
+                                               const unsigned char* copyPtr,
+                                               int width, int height) {
     SkASSERT(NULL != distanceField);
     SkASSERT(NULL != copyPtr);
 
     // we expand our temp data by one more on each side to simplify
     // the scanning code -- will always be treated as infinitely far away
     int pad = SK_DistanceFieldPad + 1;
 
     // set params for distance field data
     int dataWidth = width + 2*pad;
     int dataHeight = height + 2*pad;
@@ skipping 167 matching lines @@
                 *currDestPtr++ = (mask & (1 << i)) ? 0xff : 0;
             }
         }
         currSrcScanLine += rowBytes;
         *currDestPtr++ = 0;
     }
     sk_bzero(currDestPtr, (width+2)*sizeof(char));
 
     return generate_distance_field_from_image(distanceField, copyPtr, width, height);
 }