fix (some) 64bit warnings -- size_t -> int

src/core/SkError.cpp

 
 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTLS.h"
 #include "SkTypes.h"
@@ skipping 112 matching lines @@
             break;
         case kParseError_SkError:
             error_name = "Parse Error";
             break;
         default:
             error_name = "Unknown error";
             break;
     }
 
     sprintf( str, "%s: ", error_name );
-    int string_left = ERROR_STRING_LENGTH - strlen( str );
+    int string_left = SkToInt(ERROR_STRING_LENGTH - strlen(str));
     str += strlen(str);
 
     va_start( args, fmt );
     vsnprintf( str, string_left, fmt, args );
     va_end( args );
     SkErrorCallbackFunction fn = THREAD_ERROR_CALLBACK;
     if (fn && code != kNoError_SkError) {
         fn(code, THREAD_ERROR_CONTEXT);
     }
 }