fix more 64bit warnings

gm/offsetimagefilter.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 "gm.h"
 #include "SkOffsetImageFilter.h"
 #include "SkBitmapSource.h"
@@ skipping 69 matching lines @@
     virtual void onDraw(SkCanvas* canvas) {
         if (!fInitialized) {
             make_bitmap();
             make_checkerboard();
             fInitialized = true;
         }
         canvas->clear(0x00000000);
         SkPaint paint;
 
         int x = 0, y = 0;
-        for (size_t i = 0; i < 4; i++) {
+        for (int i = 0; i < 4; i++) {
             SkBitmap* bitmap = (i & 0x01) ? &fCheckerboard : &fBitmap;
             SkIRect cropRect = SkIRect::MakeXYWH(i * 12,
                                                  i * 8,
                                                  bitmap->width() - i * 8,
                                                  bitmap->height() - i * 12);
             SkImageFilter::CropRect rect(SkRect::Make(cropRect));
             SkAutoTUnref<SkImageFilter> tileInput(SkNEW_ARGS(SkBitmapSource, (*bitmap)));
             SkScalar dx = SkIntToScalar(i*5);
             SkScalar dy = SkIntToScalar(i*10);
             SkAutoTUnref<SkImageFilter> filter(SkNEW_ARGS(
@@ skipping 12 matching lines @@
     SkBitmap fBitmap, fCheckerboard;
     bool fInitialized;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new OffsetImageFilterGM; }
 static GMRegistry reg(MyFactory);
 
 }