Don't show a placeholder if the response contains the full image.

third_party/WebKit/Source/platform/network/HTTPParsers.h

 /*
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2011 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
@@ skipping 22 matching lines @@
 
 #include "platform/PlatformExport.h"
 #include "platform/json/JSONValues.h"
 #include "wtf/Allocator.h"
 #include "wtf/Forward.h"
 #include "wtf/HashSet.h"
 #include "wtf/Vector.h"
 #include "wtf/text/StringHash.h"
 
 #include <memory>
+#include <stdint.h>
 
 namespace blink {
 
 class Suborigin;
 class ResourceResponse;
 
 typedef enum {
   ContentDispositionNone,
   ContentDispositionInline,
   ContentDispositionAttachment,
@@ skipping 108 matching lines @@
                                                    size_t* end);
 
 // Parses a header value containing JSON data, according to
 // https://tools.ietf.org/html/draft-ietf-httpbis-jfv-01
 // Returns an empty unique_ptr if the header cannot be parsed as JSON. JSON
 // strings which represent object nested deeper than |maxParseDepth| will also
 // cause an empty return value.
 PLATFORM_EXPORT std::unique_ptr<JSONArray> parseJSONHeader(const String& header,
                                                            int maxParseDepth);
 
+// Extracts the values in a Content-Range header and returns true if they are
+// valid for a 206 response; otherwise returns false.
+// The following values will be outputted:
+// |*firstBytePosition| = inclusive position of the first byte of the range
+// |*lastBytePosition| = inclusive position of the last byte of the range
+// |*instanceLength| = size in bytes of the object requested
+// If any of the above values is unknown, its value will be -1.
+PLATFORM_EXPORT bool parseContentRangeHeader(const String& contentRange,
+                                             int64_t* firstBytePosition,
+                                             int64_t* lastBytePosition,
+                                             int64_t* instanceLength);
+
 }  // namespace blink
 
 #endif