Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/platform/fonts/mac/FontCacheMac.mm

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 98 matching lines @@
     NSFont *nsFont = platformData.font();
 
     NSString *string = [[NSString alloc] initWithCharactersNoCopy:codeUnits length:codeUnitsLength freeWhenDone:NO];
     NSFont *substituteFont = [NSFont findFontLike:nsFont forString:string withRange:NSMakeRange(0, codeUnitsLength) inLanguage:nil];
     [string release];
 
     // FIXME: Remove this SPI usage: http://crbug.com/255122
     if (!substituteFont && codeUnitsLength == 1)
         substituteFont = [NSFont findFontLike:nsFont forCharacter:codeUnits[0] inLanguage:nil];
     if (!substituteFont)
-        return 0;
+        return nullptr;
 
     // Chromium can't render AppleColorEmoji.
     if ([[substituteFont familyName] isEqual:@"Apple Color Emoji"])
-        return 0;
+        return nullptr;
 
     // Use the family name from the AppKit-supplied substitute font, requesting the
     // traits, weight, and size we want. One way this does better than the original
     // AppKit request is that it takes synthetic bold and oblique into account.
     // But it does create the possibility that we could end up with a font that
     // doesn't actually cover the characters we need.
 
     NSFontManager *fontManager = [NSFontManager sharedFontManager];
 
     NSFontTraitMask traits;
@@ skipping 79 matching lines @@
 
     // FontPlatformData::font() can be null for the case of Chromium out-of-process font loading.
     // In that case, we don't want to use the platformData.
     OwnPtr<FontPlatformData> platformData = adoptPtr(new FontPlatformData(platformFont, size, fontDescription.usePrinterFont(), syntheticBold, syntheticOblique, fontDescription.orientation(), fontDescription.widthVariant()));
     if (!platformData->font())
         return 0;
     return platformData.leakPtr();
 }
 
 } // namespace WebCore