Do not show image placeholders for CSS sprites

third_party/WebKit/Source/core/css/CSSImageSetValue.h

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef CSSImageSetValue_h
 #define CSSImageSetValue_h
 
 #include "core/css/CSSValueList.h"
 #include "platform/CrossOriginAttributeValue.h"
+#include "platform/loader/fetch/FetchParameters.h"
 #include "platform/weborigin/Referrer.h"
 #include "platform/wtf/Allocator.h"
 
 namespace blink {
 
 class Document;
 class StyleImage;
 
 class CSSImageSetValue : public CSSValueList {
  public:
   static CSSImageSetValue* Create() { return new CSSImageSetValue(); }
   ~CSSImageSetValue();
 
   bool IsCachePending(float device_scale_factor) const;
   StyleImage* CachedImage(float device_scale_factor) const;
   StyleImage* CacheImage(
       const Document&,
       float device_scale_factor,
-      CrossOriginAttributeValue = kCrossOriginAttributeNotSet);
+      CrossOriginAttributeValue = kCrossOriginAttributeNotSet,
+      FetchParameters::PlaceholderImageRequestType =
+          FetchParameters::kDisallowPlaceholder);

[kouhei (in TOK), 2017/04/28 03:50:50]

Option 1. [Preferred] Can we make this non-optional param?
Option 2. Should the default be kAllowPlaceholder now that most of the callers
are specifying kAllowPlaceholder?

[Raj, 2017/04/28 18:01:21]

Made it non-optional.

 
   String CustomCSSText() const;
 
   struct ImageWithScale {
     DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
     String image_url;
     Referrer referrer;
     float scale_factor;
   };
 
@@ skipping 19 matching lines @@
   Member<StyleImage> cached_image_;
 
   Vector<ImageWithScale> images_in_set_;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSImageSetValue, IsImageSetValue());
 
 }  // namespace blink
 
 #endif  // CSSImageSetValue_h