fix int -> bool warning

src/utils/SkLua.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 "SkLua.h"
 #include "SkCanvas.h"
 #include "SkPaint.h"
@@ skipping 34 matching lines @@
 template <typename T> T* get_ref(lua_State* L, int index) {
     const T* ref = NULL;
     return *(T**)luaL_checkudata(L, index, get_mtname(*ref));
 }
 
 template <typename T> T* get_obj(lua_State* L, int index) {
     const T* obj = NULL;
     return (T*)luaL_checkudata(L, index, get_mtname(*obj));
 }
 
+static bool lua2bool(lua_State* L, int index) {
+    return !!lua_toboolean(L, index);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 static void setfield_string(lua_State* L, const char key[], const char value[]) {
     lua_pushstring(L, value);
     lua_setfield(L, -2, key);
 }
 
 static void setfield_number(lua_State* L, const char key[], double value) {
     lua_pushnumber(L, value);
     lua_setfield(L, -2, key);
@@ skipping 172 matching lines @@
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 static int lpaint_isAntiAlias(lua_State* L) {
     lua_pushboolean(L, get_obj<SkPaint>(L, 1)->isAntiAlias());
     return 1;
 }
 
 static int lpaint_setAntiAlias(lua_State* L) {
-    get_obj<SkPaint>(L, 1)->setAntiAlias(lua_toboolean(L, 2));
+    get_obj<SkPaint>(L, 1)->setAntiAlias(lua2bool(L, 2));
     return 0;
 }
 
 static int lpaint_getColor(lua_State* L) {
     SkLua(L).pushColor(get_obj<SkPaint>(L, 1)->getColor());
     return 1;
 }
 
 static int lpaint_setColor(lua_State* L) {
     get_obj<SkPaint>(L, 1)->setColor(lua2color(L, 2));
@@ skipping 207 matching lines @@
         lua_pop(L, 1); /* pop off the meta-table */ \
     } while (0)
 
 void SkLua::Load(lua_State* L) {
     REG_CLASS(L, SkCanvas);
     REG_CLASS(L, SkPath);
     REG_CLASS(L, SkPaint);
     REG_CLASS(L, SkRRect);
 }