Fix two harmless int-to-pointer conversions that a new clang warns about.

skia/ext/skia_utils_mac.mm

 // Copyright (c) 2012 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 "skia/ext/skia_utils_mac.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
@@ skipping 56 matching lines @@
     [image drawInRect:drawRect
              fromRect:NSZeroRect
             operation:NSCompositeCopy
              fraction:1.0];
   } else {
     [image_rep drawInRect:drawRect
                  fromRect:NSZeroRect
                 operation:NSCompositeCopy
                  fraction:1.0
            respectFlipped:NO
-                    hints:NO];
+                    hints:nil];
   }
 
   [NSGraphicsContext restoreGraphicsState];
 
   return bitmap;
 }
 
 } // namespace
 
 namespace gfx {
@@ skipping 316 matching lines @@
   // Apply content matrix.
   SkMatrix skMatrix = canvas_->getTotalMatrix();
   skMatrix.postTranslate(-SkIntToScalar(pt.fX), -SkIntToScalar(pt.fY));
   CGAffineTransform affine = SkMatrixToCGAffineTransform(skMatrix);
   CGContextConcatCTM(cgContext_, affine);
   
   return cgContext_;
 }
 
 }  // namespace gfx